PART II. Palaeontology of the Brachiopoda

PALAEONTOLOGY OF THE BRACHIOPODA

F. R. COWPER REED, B.A., F.G.S.

Trinity College, Cambridge

CHAPTER XVIII

PALAEONTOLOGY OF THE BRACHIOPODA

INTRODUCTION--DIVISION I. ECARDINES--EXTERNAL CHARACTERS--INTERNAL CHARACTERS--DIVISION II. TESTICARDINES--EXTERNAL CHARACTERS--INTERNAL CHARACTERS--SYNOPSIS OF FAMILIES--STRATIGRAPHICAL DISTRIBUTION--PHYLOGENY AND ONTOGENY

=Introduction=

The wide distribution and vast abundance of the Brachiopoda throughout the whole series of geological formations make this group of especial importance to the student of the past history of the earth; and the zoologist must always regard the fossil forms with peculiar interest, because they not only largely outnumber the living representatives, but comprise numerous extinct genera, and even families, exhibiting types of structure and characters entirely absent in the modern members of the group. It is a most fortunate circumstance that the excellent state of preservation in which we frequently find them, and the immense amount of material at our disposal, enable us to determine with accuracy and certainty the internal characters of the shells in the great majority of cases. But it is only since the beginning of the present century that our knowledge of the anatomy of the soft parts of the living animal has rendered any tracing of homologies possible. In the case of features in fossil extinct types the interpretation must be to some extent doubtful. Barrande, Clarke, Davidson, Hall, King, Oehlert, Waagen, de Verneuil, and a host of other workers have contributed to the information which we now possess; and their works must be consulted for details of the subject.

Since all Brachiopods are inhabitants of the sea, the geologist at once recognises as a marine deposit any bed which contains their remains. Under favourable conditions they swarmed in the seas of Palaeozoic and Mesozoic times. Beds of limestone are frequently almost entirely composed of their shells, as, for instance, some of the Devonian limestones of Bohemia. Often they give the facies to the fauna and outnumber in species and individuals all the other organisms of the period. The Ungulite Sandstone (Cambrian) of Russia and the Productus Limestone of the Salt Range in India of Carboniferous and Permian age are well-known examples.

Many species seem to have been gregarious in habit; thus Productus giganteus of the Carboniferous Limestone may generally be found in crowded masses, as in some localities in Yorkshire.

The fact that certain species of Brachiopods characterise definite stratigraphical horizons or “zones” gives them occasionally an importance equal to that of Graptolites; for instance, the Ecardinate species Trematis corona marks a set of beds in the Ordovician, and the isolated Stringocephalus Burtini is restricted to the upper part of the Middle Devonian, giving to the limestone on that horizon its distinctive name. It is noteworthy also how certain species affect a sandy and others a calcareous sea-bottom, so that beds of the same age show differences in their Brachiopod fauna owing to a dissimilar lithological composition.

While few of the recent Brachiopods reach a large size, some of the extinct species measure several inches in breadth, but the great Productus giganteus attained the width of even a foot.

The bright colours of the shells of the living animals are not generally preserved amongst the fossil species from the older rocks; yet in a Carboniferous Terebratula we can even now detect the purple bands in some specimens, and a Cretaceous Rhynchonella similarly exhibits its original colour.

The Brachiopoda are evidently a group in its decline, as the geological record shows; but they date back from the earliest known fossiliferous rocks, in which the Ecardinate division is alone represented. As we ascend through the stratigraphical series the number and variety of genera and species belonging to both divisions rapidly increase until in the united Ordovician and Silurian there are nearly 2000 species and about 70 genera. From this point of maximum development down to the present day there is a gradual decrease in numbers.

According to Davidson, at least 17 Upper Tertiary species are still living on our sea-bottoms; and many recent Mediterranean forms occur in the Pliocene rocks of the islands and shores of that sea, and in the Crags of East Anglia.

A brief review of the chief characteristics of fossil Brachiopoda is given below. Those genera which have the greatest zoological or geological importance can alone be noticed owing to the exigencies of space.

I. ECARDINES

=External Characters=

A considerable diversity of external form is met with even in this division, from the limpet-like Discina to the flattened tongue-shaped Lingula. The valves have most commonly a smooth external surface with delicate growth-lines; but sometimes pittings (Trematis) or radiating ribs (Crania) are present, and in a few forms the shell is furnished with spines (Siphonotreta), which perhaps serve to anchor it in the soft mud of the sea-bottom. The usual mode of fixation was by means of the pedicle (= peduncle or stalk), which either (1) passed out simply between the posterior gaping portion of the valves (Lingula), or (2) lay in a slit in the ventral valve (Lingulella), or (3) pierced the substance of the latter valve by a definite foramen (Discina). The first-mentioned condition of the pedicle seems the most primitive. Rarely the pedicle was absent, and the shell was attached by the whole surface of the ventral valve (Crania, p. 467).

The two valves in the fossil Ecardines were held together by muscular action, though in some families (Trimerellidae) we see traces of articulating processes. The “hinge line,” or line along which the valves worked as on a hinge, is in most forms more or less curved. A “hinge area” (i.e. that portion of the shell generally smoother than other parts of the valves, more or less triangular in form, and lying between the beaks on one or both sides of the hinge line), is usually absent in the Ecardines.

=Internal Characters=

Owing to the rarity of well-preserved interiors of valves in this division, our knowledge of their internal characters is still far from satisfactory. The arrangement of the muscular impressions varies greatly amongst extinct genera, but we are often able to interpret them with a considerable amount of certainty by a study of the scars and the muscles of the well-known recent Lingula (Fig. 322). The extreme specialisation of the muscles in many of the earliest genera (e.g. Lingula) is remarkable, and points to a long but so far undiscovered ancestry in pre-Cambrian times. In fossil species of Crania and Lingula the muscle-scars correspond closely with those in the living representatives of these genera. In the most highly specialised family of the Ecardines--the Trimerellidae--we meet with features of peculiar interest. The muscle-scars in this family (Fig. 323, A, B) are most remarkable for the development of the so-called “crescent,” (q.r.s.) which skirts the posterior margin of both valves as a sub-cardinal impression. It is believed to be the trace of a strong post-parietal muscular wall, analogous in position to that of Lingula. The three pairs of “lateral” muscle-scars in the latter genus seem to be represented by the “terminal” (s) and “lateral” (r) scars on the crescent of the Trimerellidae. A pair of “transverse” scars (t) occurs in each valve between the “terminals” and the antero-lateral edge of the “platform” (j). “Cardinal” (v), “sub-cardinal” (w), and “umbo-lateral” (x) scars also occur. The median impression which covers the “platform” (j) consists of a central, lateral, and usually an anterior pair of scars; and the impressions of the genital organs, according to Davidson and King, lie medianly posterior to the “platform.” The “platform” itself is a more or less conspicuous central calcareous elevated area occurring in each valve, but most developed in the dorsal; in some cases it is double-chambered with tubular cavities (“platform vaults,” Fig. 323, A, B, k), in others it is more or less solid. It appears to have originated through a posterior shifting of the central muscular bands, that they might be inserted behind the liver; at the same time a deposition of shelly material, to form fulcra to work the heavy valves, took place at these points. The tunnelling-out of the platform was probably due to the continual pressure of the lobes of the liver. The division of the umbonal cavity into definite chambers in Monomerella, and to a less extent in other members of this family, appears, according to Davidson and King, to have been caused by pressure of the ovarian lobes.

In connexion with the foregoing remarks on the development of the “platform,” it may be mentioned that the paths along which the muscle-bands move, as the shell of Brachiopods increases in size, are marked by elongated scars, and often by shelly deposits; and when the members of a muscle-pair come into juxtaposition these shelly deposits (which act as fulcra for the muscles) combine, and by the growth of the shell form a septum, as in the case of the median septum of Lingulepis.

The Obolidae show some important features in the internal impressions. Obolella crassa (Hall) may be taken as a well-known type of the family. In this species a pair of small scars, one on each side of the pedicle-groove, lies close under the hinge line in the ventral valve. There is also a well-marked scar for the insertion of the pedicle-muscle at the end of the pedicle-groove. A pair of much elongated lateral impressions extending forward from the “cardinals” may be homologous with the “laterals” of Lingula; and the two small central scars between them may be compared with the “centrals” of Lingula which are in a somewhat similar position. In the dorsal valve of O. crassa a pair of “cardinals” is found, and on each side of a low median rounded ridge are two small “central” scars. Indistinct “lateral” scars arise close to or in the central area, and diverge anteriorly.

Sometimes a great concentration of muscle-scars occurs round the foramen in the ventral valve, as in Siphonotreta.

As regards the minute structure and composition of the shell in the Ecardines, we find that the Lingulidae and Discinidae have their shell composed of alternating layers of phosphate of lime and a corneous substance; the former layers are pierced by microscopic canals. The Craniidae have calcareous shells traversed by tubules, which divide into many fine branches near the external surface; a thin periostracum covers the exterior. The Trimerellidae have heavy thick calcareous shells, for which they required the previously-described elaborate arrangement of muscles to open and shut them.

II. TESTICARDINES

=External Characters=

It is to this division that the great majority of the Brachiopoda belong; and the diversity of form, of ornamentation, and of internal characters is correspondingly greater than in the Ecardines.

A transversely or longitudinally oval shape of shell is the commonest; but sometimes it is triangular, as in Rhynchonella (Fig. 327), or bilobed, as in Pygope (= Terebratula diphya). The ventral valve is usually more convex than the dorsal, and the former may be prolonged into a tube by the accelerated growth and infolding of the anterior and lateral margins, producing a very abnormal form (Proboscidella). The external surface of the valves is frequently ornamented with more or less prominent radiating ribs; and fine concentric growth-lines are commonly shown, and may be developed into coarse ridges or wrinkles, particularly in old individuals. The members of the family Productidae are usually furnished with tubular spines, which are sometimes of great length, and served to anchor the free shells in the mud, or were twisted round Crinoid stems and similar objects.

In the ventral valve of many genera there is a median sinus, with a corresponding fold in the dorsal valve, and rarely vice versâ; sometimes the fold and sinus are double.

The hinge line is either curved or straight, and the valves are articulated by means of a pair of “hinge-teeth” (Fig. 329, t) in the ventral valve, which fit into corresponding sockets in the opposite valve. Some genera have the teeth very rudimentary, or have lost them altogether. The teeth are frequently supported by “dental plates,” and the sockets by “socket plates” (e.g. Conchidium, Figs. 324, 325). A few genera with a long hinge line have the whole of it denticulated (Stropheodonta). In the dorsal valve medianly close under the hinge line is a shelly protuberance--the “cardinal process”--to which the diductor muscles are attached. It is sometimes of great length and forked (Stringocephalus, Fig. 326), or tripartite, or even quadripartite; but in Rhynchonella and some other genera it is rudimentary.

A “hinge area” (Fig. 334, c.a) is often present on one or both valves, and may be of great size, as in Clitambonites, but in Productus it is wholly absent. In those genera that possess it a triangular fissure--the “deltidial fissure”--frequently traverses it on both valves; in the dorsal valve the fissure is merely the space between the dental sockets, and may be occupied by the cardinal- process (Fig. 334, C) or covered by a shelly plate--the “chilidium.” In the ventral valve it gives passage to the pedicle, and may be partly or entirely closed by a similar plate (Fig. 334, d) known as the “pseudo-deltidium,” especially large in Clitambonites, or remain open (Orthis). This pseudo-deltidium is a primitive character, and arises in an early stage of the development as a shell-growth on the dorsal side of the animal, becoming attached to the ventral valve subsequently. The pedicle in many genera passes out through a special foramen in the beak of the ventral valve; and its proximal portion is often embraced by a pair of small plates--the deltidial plates or “deltidium”--which are formed on lateral extensions of the ventral mantle lobe, according to Beecher. These plates lie on each side of the pedicle, or grow round and unite in front of it (Rhynchonella, Fig. 327), or constitute merely its anterior border (Terebratula, Fig. 328). In some cases this foramen becomes closed in old age.

The dorsal valve in a few cases has its beak perforated by a foramen--the “visceral foramen.” This foramen is in no way connected with the pedicle foramen, but points perhaps to the existence in the early Testicardinate genera of an anal aperture. In Athyris concentrica (Devonian) this foramen is connected internally with a cylindrical tube, which extends longitudinally to about one-third the length of the valve. In Centronella the aperture in the cardinal plate is rounded and complete; and in Strophomena and its allies the opening lies between the cardinal processes. If this feature is correctly interpreted, it suggests a retrogression of the group since Palaeozoic times not only in numbers, but in structure; and other evidence points the same way.

=Internal Characters=

The interior of the shell is sometimes more or less divided up by septa. A median septum occurs in one or both valves of many genera as a low ridge or strongly developed partition (Waldheimia, Fig. 329, ss; and Stringocephalus, Fig. 326, B, v.s). Conchidium (Fig. 325) has its dental plates of great size, and uniting to form a V-shaped chamber or “spondylium,” supported by a median double septum; and by means of these with a pair of septa and the large socket-plates in the dorsal valve the interior of the shell of this genus is divided up into several chambers.

The interiors of several other genera are somewhat similarly divided up.

In the Carboniferous genus Syringothyris two special plates, situated between the dental plates, are rolled into an incomplete tube, so as to enclose probably the anal extremity of the alimentary canal; and in several genera a sub-umbonal “cardinal plate” is present, which is perforated (Athyris) or slit in some cases for the passage of the anal tube.

For the support of the fleshy “spiral arms” the calcareous structures forming the “brachial apparatus” are of two main types--(1) the loop type; (2) the spiral-cone type. In the Strophomenidae no special calcareous support seems to have been usually present (Fig. 334), though in some species of Leptaena spirally-grooved elevated areas supported the fleshy arms; in the Productidae it is probable that the ridges enclosing the “reniform impressions” (Fig. 333, i) served for a similar purpose.

The Terebratulidae show the “loop type” of brachial apparatus. In Waldheimia (Fig. 329), which may be taken as an example, we notice first in the dorsal valve the “crura” (cr), from which arise the two “descending branches” which run forwards and then are bent back to form the “ascending branches” which are united by the “transverse band.” In some genera the “ascending branches” may be reduced to mere points, and the “transverse band” become a median vertical plate; the “crura,” too, may be fused so as to form a “crural band”; and the “descending branches” may be connected by a cross band--the “jugal band.” In Stringocephalus (Fig. 326, l, s.p) the loop is furnished on its inner edge with radiating processes; and in Argiope the loop is simple, not reflected, and fused with marginal septa; while in the Thecidiidae it is more or less fused with the shell itself, and with the mass of calcareous spicules secreted by the mantle.

The “spiral-cone type” of brachial apparatus is found in the Spiriferidae, Atrypidae, and Koninckinidae, and consists of two spirally-enrolled calcified lamellae, forming two cones with their apices directed laterally (Spirifera, Fig. 330), or towards the interior of the dorsal valve (Atrypa, Fig. 332), or towards each other (Glassia); or forming two flat spirals in the same plane (Koninckinidae). A “jugal band” is generally present, but varies much in position, and in some genera has complicated posterior processes.

The Rhynchonellidae have no loop or spiral cones, but merely a pair of short “crura.”

The principal modifications in the attachments of the muscles in the Testicardines are illustrated by Productus giganteus (Fig. 333), Leptaena rhomboidalis (Fig. 334), and Waldheimia flavescens (Fig. 329).

In Productus (Fig. 333) we see in the ventral valve a pair of dendritic occlusor, often called adductor, impressions and a pair of large flabellate divaricator impressions. In the dorsal valve the large “cardinal process” served for the attachment of the divaricator, and a low median septum separated the dendritic occlusor scars, which are rarely divisible into anterior and posterior pairs.

In Leptaena (Fig. 334) the occlusor scars (a) in the ventral valve are narrow and median, and are enclosed by a pair of flabelliform divaricator impressions (d.v); in the dorsal valve two pairs of occlusor scars (a.a, p.a) are well marked, and accessory posterior occlusor scars are traceable in some specimens. The vascular sinuses (v.s) and genital areas are conspicuous in many species of this and other genera.

In Waldheimia (Fig. 329) a sub-umbonal “peduncular muscle” scar (p) in the ventral valve has before it a pair of “accessory divaricator” scars (a.d) flanked by a pair of “ventral adjustor” (v.a) and a pair of “divaricator” impressions (d), between which lie the two occlusor scars (a). In the dorsal valve anterior and posterior pairs of occlusor scars (a.a, a.p) are visible.

The minute structure of the calcareous shell of the Testicardines is of flattened fibrous prisms inclined at a very acute angle to the surfaces. In many forms minute tubes more or less closely arranged pierce through the fibrous shell-substance; but in some genera (Productus) they do not reach the outer surface (see p. 468). Allied genera, however, differ much in the punctate or impunctate character of the shell.

SYNOPSIS OF FAMILIES

I. ECARDINES

Family. Lingulidae

Shell elongated, composed of alternating chitinous and calcareous layers, the latter of which are perforated. Attached by a pedicle passing between apices of valves.

Arms have no calcified supports.

(For muscles see Fig. 322.)

RANGE.--Lower Cambrian to Recent.

PRINCIPAL GENERA.--Lingula, Lingulella, Lingulepis.

Family. Obolidae

Shell varies in shape. Ventral valve provided with pedicular groove or foramen. Cardinal border thickened. No brachial supports. Shell composed of alternating chitinous and calcareous layers.

(For muscles see p. 496.)

RANGE.--Lower Cambrian to Devonian.

PRINCIPAL GENERA.--Obolus, Obolella, Kutorgina, Linnarssonia, Siphonotreta, Acrotreta, Neobolus.

Family. Discinidae

Shell rounded, valves more or less conical, fixed by pedicle passing through slit or tubular foramen in ventral valve. No calcified brachial supports. Shell structure chitino-calcareous.

RANGE.--Ordovician to Recent.

PRINCIPAL GENERA.--Discina, Orbiculoidea, Trematis.

Family. Craniidae

Shell calcareous, subcircular; fixed by surface of ventral valve; dorsal valve the larger, depressed-conical. Shell structure punctate.

Four principal muscular scars in each valve, with central triangular protuberance in ventral valve (see p. 476).

RANGE.--Ordovician to Recent.

PRINCIPAL GENUS.--Crania.

Family. Trimerellidae

Shell thick, calcareous, inequivalve; beak of ventral valve usually prominent; rudimentary teeth maybe present; hinge area well developed, with pseudo-deltidium. In interior of valves muscular platform, “crescent,” and sometimes sub-umbonal chambers (see p. 494, Fig. 323).

RANGE.--Ordovician and Silurian; maximum in Wenlock.

PRINCIPAL GENERA.--Trimerella, Monomerella, Dinobolus, Rhinobolus.

II. TESTICARDINES

Family. Productidae

Shell entirely free, or fixed by ventral valve or spines. Concavo-convex, more or less covered with tubular spines. Hinge line straight. Hinge-teeth absent or rudimentary.

Cardinal process prominent.

Reniform impressions in dorsal valve.

(For muscular impressions see p. 501, Fig. 333.)

RANGE.--Silurian to Permian. Genus Productus very characteristic of the Carboniferous.

PRINCIPAL GENERA.--Productus, Chonetes, Strophalosia, Proboscidella, Aulosteges.

Family. Strophomenidae

Shell very variable in shape; concavo-convex, plano-convex, or biconvex; hinge line usually straight; frequently with an area on each valve; foramen may or may not be present. Shell structure near always punctate. Ventral valve usually furnished with hinge-teeth; and dorsal valve with cardinal process.

Brachial supports completely absent or very rudimentary.

(For muscular impressions see p. 502, Fig. 334.)

RANGE.--Wholly Palaeozoic.

PRINCIPAL GENERA.--Orthis, with many sub-genera, Clitambonites, Skenidium, Strophomena, Orthothetes, Leptaena, Stropheodonta, Plectambonites.

Family. Koninckinidae

Shell plano-convex or concavo-convex. Brachial apparatus composed of two lamellae spirally enrolled in the same plane, or in the form of depressed cones, with the apices directed into the ventral valve.

RANGE.--Silurian to Lias.

PRINCIPAL GENERA.--Koninckina, Koninckella, Coelospira, Davidsonia.

Family. Spiriferidae

Shell biconvex. Brachial apparatus consisting essentially of two descending calcareous lamellae which by spiral enrolment form a pair of laterally-directed cones (Fig. 330).

RANGE.--Chiefly Palaeozoic, but a few forms pass up into the Lias.

PRINCIPAL GENERA.--Spirifera, Cyrtia, Uncites, Athyris, Merista.

Family. Atrypidae

Brachial apparatus consists of two descending calcareous lamellae which bend outwards at the extremity of the crura and are coiled into two spiral cones, the apices of which either converge towards each other (Glassia) or towards the dorsal valve (Atrypa, Fig. 332), or diverge towards the dorsal valve (Dayia); shell structure impunctate.

RANGE.--Ordovician to Trias.

PRINCIPAL GENERA.--Atrypa, Dayia, Glassia.

Family. Rhynchonellidae

Shell biconvex, hinge line usually curved.

Beak of ventral valve incurved, with foramen.

Calcareous brachial supports reduced to a pair of short curved crura.

The septa, dental and socket plates may be highly developed and divide up the cavity of the shell into chambers (Stenochisma, Conchidium).

Shell structure fibrous, rarely punctate; muscular impressions as in Terebratulidae.

RANGE.--Ordovician to Recent: majority of the genera are Palaeozoic.

PRINCIPAL GENERA.--Rhynchonella (Fig. 327), Stenochisma, Stricklandia, Conchidium.

Family. Terebratulidae

Shell structure punctate.

Arms supported by a calcareous loop, usually bent back on itself.

(For muscular impressions see p. 502, Figs. 328, 329.)

Beak of ventral valve perforated by foramen, furnished with deltidium.

RANGE.--Devonian to Recent; maximum development in Mesozoic times.

PRINCIPAL GENERA.--Terebratula, Terebratulina, Waldheimia, Terebratella, Kingena, Magas, Centronella.

Family. Argiopidae

Large foramen for passage of pedicle. Marginal septa present in both valves. Calcareous brachial loop follows margin of shell and is more or less fused with the septa. Shell structure punctate.

RANGE.--Jurassic to Recent.

PRINCIPAL GENERA.--Argiope, Cistella.

Family. Stringocephalidae

Shell subcircular, punctate. Cardinal process highly developed, bifid. Brachial apparatus composed of two calcareous free lamellae, prolonged at first downwards, then bent back, upwards and outwards to run parallel to margin of shell and to unite in front, thus constituting a wide loop.

RANGE.--Silurian and Devonian.

SOLE GENUS.--Stringocephalus.

Family. Thecidiidae

Shell usually fixed by beak of ventral valve, plano-convex. Sub-cardinal apophysis in ventral valve for attachment of occlusors. Marginal septa in dorsal valve. Calcareous brachial loop more or less fused with shell, and with calcareous spicules of mantle. Shell structure: inner layer fibrous, outer layer tubulated.

RANGE.--Carboniferous to Recent.

PRINCIPAL GENERA.--Thecidium, Oldhamina.

STRATIGRAPHICAL DISTRIBUTION OF BRACHIOPODA

It is remarkable that some of the earliest types of Brachiopoda exist generically unchanged at the present day. Such are Lingula, ranging from the Cambrian; Discina and Crania, ranging from the Ordovician; and amongst the hinged forms Terebratula from the Devonian, and Rhynchonella from the Ordovician.

In the lowest Cambrian (Olenellus beds) the most important genera are Linnarssonia and Kutorgina. The hinged forms appear in the Cambrian, being represented by Orthis; but the majority in this formation belong to the Ecardines. Lingula, Lingulella, and Obolella are characteristic.

In the Ordovician many new genera of the Testicardines make their appearance, such as Strophomena, Leptaena, Atrypa, Rhynchonella, Clitambonites, etc., but the extraordinary abundance and variety of Orthis is most remarkable. The Ecardines are reinforced by such forms as Trematis and Siphonotreta. It is, however, in the Silurian that the Testicardinate Brachiopoda attain their maximum, for in addition to a great development of species amongst the older forms, a host of new genera for the first time occur here (Spirifera, Athyris, Conchidium, Stricklandia, Chonetes, Cyrtia, etc.); and the Trimerellidae are especially characteristic of the Wenlock.

With the commencement of Devonian times many species and genera become extinct, but new forms come in (Terebratula, Orthothetes, Productus, etc.), and some genera are wholly confined to this formation (Uncites, Stringocephalus). The Carboniferous is marked by the maximum development of Productus and Spirifera; Orthothetes, Stenochisma, and Athyris are also abundant, but there is a considerable extinction of the older genera and species, and a great diminution in the number of individuals and species of those that persist.

A further reduction occurs in the Permian, where the most important genera are Productus, Strophalosia, and Stenochisma; but Aulosteges is a new form peculiar to this period. In the Trias a new era commences; the principal families and genera of the older rocks disappear entirely; a few spire-bearing genera persist (Spiriferina, Athyris), and the genus Koninckina is restricted to this formation.

The enormous development of species of the Terebratulidae and Rhynchonellidae is the most noticeable feature in Jurassic times; and a few ancient types linger on into the Lias (Spiriferina, Suessia, a sub-genus of Spirifera); Koninckella here occurs.

The Cretaceous Brachiopoda are closely allied to the Jurassic; Magas and Lyra are peculiar to the period, and the Terebratulidae and Rhynchonellidae are very abundant, together with the Ecardinate genus Crania.

With the commencement of Tertiary times the Brachiopoda have lost their geological importance, and have dwindled down into an insignificant proportion of the whole Invertebrate fauna.

* * * * *

The distribution of the Brachiopoda in past time is shown in the following table:--

+------------------------------------+-----------------------+-----------+-------+ | | Palaeozoic | Mesozoic | | | | | | | | C | | | | | | | | | | | | | a | | | | | | | | | | | | | r | | | | | | | | | | O | | | b | | | | C | | | | | | r | | | o | | | | r | | | | | C | d | S | D | n | | | J | e | T | | | | a | o | i | e | i | P | | u | t | e | | | | m | v | l | v | f | e | | r | a | r | R | | | b | i | u | o | e | r | T | a | c | t | e | | | r | c | r | n | r | m | r | s | e | i | c | | | i | i | i | i | o | i | i | s | o | a | e | | | a | a | a | a | u | a | a | i | u | r | n | | | n | n | n | n | s | n | s | c | s | y | t | | ECARDINES +---+---+---+---+---+---+---+---+---+---+---+ | Lingulidae Lingula |__|_|_|_|_|_|_|_|_|_|_| | Lingulella |_| | | | | | | | | | | | Obolidae Obolus | |_|_| | | | | | | | | | Obolella |_|_| | | | | | | | | | | Kutorgina |_|_| | | | | | | | | | | Linnarssonia |_| | | | | | | | | | | | Trematis | |_|_| | | | | | | | | | Siphonotreta | |_|_| | | | | | | | | | Acrotreta | |_| | | | | | | | | | | Discinidae Discina | |_|_|_|_|_|_|_|_|_|_| | Craniidae Crania | |_|_|_|_|_|_|_|_|_|_| | Trimerellidae Trimerella | | |_| | | | | | | | | | Dinobolus | |_| | | | | | | | | | | | | | | | | | | | | | | | TESTICARDINES | | | | | | | | | | | | | Productidae Productus | | | |_|_|_| | | | | | | Chonetes | | |_|_|_| | | | | | | | Strophalosia | | | |_|_|_| | | | | | | Strophomenidae Orthis |_|_|_|_|_| | | | | | | | Skenidium | |_|_| | | | | | | | | | Clitambonites | |_| | | | | | | | | | | Strophomena | |_|_| | | | | | | | | | Stropheodonta | |_|_|_| | | | | | | | | Leptaena | |_|_|_|_| | | | | | | | Orthothetes | | | |_|_|_| | | | | | | Davidsonia | | | |_| | | | | | | | | Koninckinidae Koninckina | | | | | | |_| | | | | | Koninckella | | | | | | | |_| | | | | Spiriferidae Spirifera | | |_|_|_|_| | | | | | | Spiriferina | | | |_|_|_|_|_| | | | | Cyrtia | | |_|_|_| | | | | | | | Syringothyris | | | | |_| | | | | | | | Uncites | | | |_| | | | | | | | | Athyris | | |_|_|_|_|_| | | | | | Merista | | |_|_| | | | | | | | | Retzia | | |_|_|_|_|_| | | | | | Atrypidae Atrypa | |_|_|_|_|_|_| | | | | | Dayia | | |_| | | | | | | | | | Coelospira | | |_| | | | | | | | | | Rhynchonellidae Rhynchonella | |_|_|_|_|_|_|_|_|_|_| | Stenochisma | | | |_|_|_| | | | | | | Stricklandia | | |_| | | | | | | | | | Conchidium | | |_|_| | | | | | | | | Terebratulidae Terebratula | | | |_|_|_|_|_|_|_|_| | Terebratulina | | | | | | | |_|_|_|_| | Waldheimia | | | | | | | |_|_|_|_| | Terebratella | | | | | | | |_|_|_|_| | Kingena | | | | | | | |_|_| | | | Magas | | | | | | | | |_| | | | Centronella | | |_|_|_| | | | | | | | Argiopidae Argiope | | | | | | | |_|_|_|_| | Cistella | | | | | | | |_|_|_|_| | Stringocephalidae Stringocephalus | | | |_| | | | | | | | | Thecidiidae Thecidium | | | | | | |_|_|_|_|_| | Oldhamina | | | | |__| | | | | | | | | | | | | | | | | | | | +------------------------------------+---+---+---+---+---+---+---+---+---+---+---+

PHYLOGENY AND ONTOGENY

Wherever successive stages in the life history of an individual resemble in important anatomical features the adult individuals of other species occurring in successive members of a stratigraphical series, the development of the individual may be regarded as an epitome of the development of the species; it also generally throws light on the origin and relationships of allied genera and families.

In the case of the fossil Brachiopoda comparatively little work has yet been done in tracing their ontogeny or phylogeny, though the abundance, variety, and excellent state of preservation of the extinct species offer a promising field for investigation. It is to Dr. C. E. Beecher and other recent American palaeontologists that we owe our advance in this branch of the subject.

In the first place, in about forty genera, representing nearly all the leading families of the group, the important fact has been established of the presence of a common form of embryonic shell, termed the “protegulum,” which is “semicircular or semielliptical in shape with a straight or arcuate hinge line and no hinge area” (Beecher). Its minute size and delicate texture cause its preservation to be rare, but its impression is not uncommonly left on the beak of the adult shell.

The main features of this embryonic shell are exhibited in the adult Lower Cambrian Brachiopod Obolus (Kutorgina) labradoricus (Billings); the sub-equal semielliptical valves have lines of growth running concentrically and parallel to the margin of the shell, and ending abruptly against the straight hinge line; and this indicates that there has been no change in the outline and proportions of the shell during its stages of growth, but only a general increase in size. It is very significant that we have here a mature type possessing the common embryonic characters of a host of widely separated genera, and we may therefore regard it as the most primitive form known.

Many genera pass through this so-called “Paterina” stage either in the case of both their valves, or more generally in the case of the dorsal valve only; but modifications in the form of the protegulum arise, which are due to the influence of accelerated growth, by which features belonging to later stages become impressed on the early embryonic shell. The most variable and specialised valve--the ventral or pedicle valve naturally exhibits the effect of this influence first and to the greatest extent. The Palaeozoic adult forms of many species represent various pre-adult stages of the Mesozoic, Tertiary, and Recent species, as is especially well shown in the genera Orbiculoidea and Discinisca.

In the Strophomenoid shells the protegulum in the dorsal valve is usually normal, but in the ventral valve abbreviation of the hinge and curvature of the hinge line are produced by acceleration of the “Discinoid stage” in which a pedicle notch is present.

No marked variation has yet been noticed in the spire-bearing, or Terebratuloid, or Rhynchonelloid genera.

The form of the shell and the amount of difference in shape and size of the valves seem to be largely due to the length of the pedicle and its inclination to the axis of the body, as evidenced by the development of Terebratulina. A series showing progressive dissimilarity of the two valves arising from these causes can be traced from Lingula to Crania. The greater alteration that takes place in the ventral valve appears to be due to its position as lower and attached valve. If the pedicle is short a transversely-expanded shell with long hinge line results when the plane of the valves is vertical or ascending, but when the latter is horizontal a Discinoid form is found. This mode of attachment is often accompanied by a more or less plainly developed radial symmetry. Shells with long pedicles, on the other hand, are usually longer than wide.

The character of the pedicle-opening is of great significance from an evolutional and classificatory point of view, for the successive stages through which it passes in embryonic growth are chronologically paralleled by different genera, and are likewise accompanied by the successive acquisition of other important anatomical characters, as has been shown by Beecher and others. The first and simplest type of pedicle opening is in shells with a posterior gaping of the valves, where the pedicle protrudes freely between them in a line with the axis, and the opening is shared by both valves, though generally to a greater extent by the ventral valve. Paterina (= Obolus labradoricus) and Lingula furnish examples of this type. In the second type the pedicle opening is restricted to the ventral valve, and the direction of the pedicle makes a right angle with the plane of the valves; in the lower forms the pedicle lies in a slit or sinus (Trematidae), but by further specialisation it becomes enclosed by shell growth so as to lie within the periphery, and finally becomes sub-central in some genera (Discinidae). The third type shows the pedicle opening confined to the ventral valve and sub-marginal. A pseudo-deltidium may preserve the original opening (Clitambonites); or this shelly plate may become worn away or reabsorbed in the adult so that the deltidial fissure through which the pedicle passes remains quite open (Orthidae). In the fourth type the incipient stage marks a return to the simple conditions of the first type; but ultimately a pair of deltidial plates develop, and may completely limit the pedicle opening below. Examples of this type are Spirifera and Rhynchonella. By means of these four types the Brachiopods have been divided into four Orders: the Atremata (type i.); the Neotremata (type ii.); the Protremata (type iii.); and the Telotremata (type iv.).

The Telotremata were the last to appear, but the four types of pedicle-opening with the various forms of calcareous brachial apparatus were in existence in the Bala period of the Ordovician.

As Paterina is the most primitive form of all, we may place it at the root of the phylogenetic tree. From it sprang the Atremata, which gave off the Neotremata and Protremata; the most primitive Neotremata seem to be the Trematidae, while the connecting link between the Protremata and Atremata is furnished by the Kutorginidae. From the genus Conchidium and its allies we may see how the Rhynchonellidae ushered in the Telotremata as an offshoot from the Protremata. The Telotremata subsequently gave off two main branches, which became specialised with the loop-bearing and spire-bearing forms respectively.

The evolution and mutual relationships of genera have been indicated with much probability by Hall, Clarke, and others. The Obolelloid type may be connected with the Linguloid by means of Lingulella and Linyulepis, while in Lingula itself we find the point of divergence for the ancestors of Trimerella, and for a line of variation culminating in Dignomia. The Palaeozoic Rhynchonelloids branched off at an early period from the same stock as Orthis, and are connecting links between this genus and Mesozoic Rhynchonellae; and a whole series of genera exhibit intermediate stages of structure between the Rhynchonelloid and Pentameroid groups. The Terebratuloids can be traced back to the primitive type Renssoellaria; and amongst spire-bearing forms, the protean genus Spirifera can be split up into groups of species which diverge along lines tending to forms no longer congeneric. When we come to deal with specific differences we find frequently such a host of intermediate varieties that the separation of many species, as in the case of Mesozoic Terebratulae, is to a large extent arbitrary and artificial.

INDEX

References to figures are printed in thick type (=248=, =197=); to systematic position, in italics (391, 430)

Abralia, 391

Absorption of internal portions of shell, 259

Abyssal Mollusca, 374

Acanthinula, 441

Acanthoceras, 399

Acanthochiton, =403=, 403

Acanthodoris, 434

Acanthopleura, 403; eyes, =188=

Acavus, 303, =304=, 335, 441

Acera, 245, 430

Achatina, 278, 328–337, =333=, 442, =443=; jaw, =211=; food, 33; size of egg, 124; A. fulica, 279

Achatinella, 278, =326=, 327, 443; radula, =234=; musical sounds, 51

Achatinelloides, 332

Acicula, 287, 296, 414

Acmaea, 405; radula, 227

Acme, 414

Acmella, 314, 415

Acroptychia, 336, 414

Acrotreta, 504, 508

Actaeon, 250, 427, =428=, 429; radula, 217, 230; streptoneurous, 203 n.

Actaeonella, 430

Actaeonia, 432

Actaeonina, 250, 429

Actinoceras, 394

Actinodonta, 447

Acusta, 306, 316, 318, 441

Adacna, =12=, 297, 455

Adalaria, 434

Adamsiella, 414

Addisonia, 412

Adelphoceras, 395

Adeorbis, 416

Admete, 426

Aegires, 434

Aegista, 305, 316, 441

Aegoceras, 398

Aeolis, =10=, =152=, 432; radula, 217, =229=; stinging cells, 65; mimicked by Sagartia, 68; warning coloration, 72

Aerope, 328, 333, 440; radula, 215; habits, 54

Aestivation, 25

Aetheria, 328–336, 452; variation, 92

Africarion, 333, 440

Agaronia, 426

Age of snails, 39

Aglossa, 7

Agnatha, habits, 51

Akiodoris, 434

Alaba, 415

Alaria, 418

Alariopsis, 420

Albersia, 320

Albino varieties, 87

Alcadia, 348–351, 410

Alderia, 432

Alexia, 439

Alicia, 459

Allognathus, 441

Allopagus, 452

Alloposidae, 384

Alvania, 415

Alycaeus, 266, 302 f., 309, 319, 414

Amalia, 440

Amalthea, 78

Amaltheus, 398

Amastra, 443

Amaura, 411

Amberleya, 409

Ambonychia, 449

Amicula, 404

Ammonites, 247, =393=, =398=, 398; sutures, =396=; aptychus, =397=

Ammonoidea, 396 f.

Amnicola, 325, 415

Amoria, radula, 222

Ampelita, 335, 442

Amphibola, 10, =18=, 439; breathing, 151; radula, 236

Amphibulimus, 352, 442; radula, 233

Amphidoxa, 358

Amphidromus, 301, 305, 317, =310=, 359, 442; radula, 233

Amphineura, 8, 400; breathing organs, 154, 168; nervous system, =203=; genitalia, 145

Amphipeplea, 439

Amphiperas, 419

Amphisphyra, 430

Amphissa, 423

Amphitretus, =383=

Ampullaria, 17, 416; self-burial, 42; spawn, =125=; breathing organs, 151, =158=; jaws, =212=; shell, =249=, 263; operculum, =268=; distribution, 294, 320, 322, 343, 359

Ampullarina, 302, 439

Ampullina, 411

Amussium, 450

Amycla, 423

Anabathron, 415

Anachis, 423

Anadenus, 24, 441

Anal glands, 241

Anal siphon, 164, 173

Anastomopsis, 442

Anatina, 274, 275, 459

Anatinacea, 458; gills, 167

Anaulus, 414

Anchistoma, 293, 296

Ancilla, 267, 426

Ancillina, 426

Ancistrochirus, 391

Ancistromesus, 405

Ancistroteuthis, 391

Ancula, 434; radula, 229, 230; warning coloration, 72

Anculotus, 417

Ancyloceras, 247, 399

Ancylus, 19, 439; breathing, 162; hibernating, 27; radula, =235=

Aneitea, 325, 443

Angitrema, 340, 417

Anisocardia, 451

Anodonta, 259, 341, 452; shower of, 47; variation, 92; Glochidium, =147=; gill, =167=; otocyst, =197=; nervous system, =206=; hinge, 274; A. anatina, 24; distribution, 282

Anodontopsis, 451

Anoglypta, 325, 441

Anomia, =257=, 448, 464; intestine, 241; byssus hole, =262=; hearing, 196

Anomiacea, 448

Anoplophora, 451

Anostoma, =248=, 266, 356, 358, 442; aperture, =63=

Anthracosia, 451

Anura, 424

Anus, 209, 241

Apera, 334, 440

Aperostoma, 344, 414

Aphanotrochus, 408

Aphelodoris, radula, 230

Apicalia, 422

Aplacophora, 9, 404; radula, 228

Aplecta, 354, 439

Aplustrum, =245=, =428=, 430; radula, 230

Aplysia, 245, =428=, 431; stomach, 239; purple fluid, 65

Aplysioidea, 430

Aporrhais, 418; radula, 215

Apricardia, 455

Aptychus, =397=

Aptyxiella, 417

Aptyxis, 424

Aral Sea, Limnaea from near, =84=; Cardium from, 91

Arca, =14=, 171, =273=, 448; eyes, =191=

Arcacea, 448

Arcachon, oyster-parks at, 105

Arcestes, 397

Archidoris, =434=, 434; protective coloration, 73

Architeuthis, 378, =390=, 390; sucker, =381=

Arcomya, 458

Arconaia, 307, 452

Arctic shells, colour of, 86

Arcuella, 422

Argiope, =470=, 472, 479, 487; parasite of, 485; distribution, 486; fossil, 501, 506, 508

Argiopidae, 506, 508

Argobuccinum, 420

Argonauta, =383=, 383; egg-laying, 127; hectocotylised arm, 137; radula, 236

Arinia, 413

Ariolimax, 441, 341; radula, 233

Arion, 440; shell, 175, 245, 246; hardier than Helix, 24; voracity, 30 f.; egg-laying, 42 f.; protective coloration, 70; pulmonary orifice, 160; food, 179; smell, 193 f.; radula, 233; distribution, 285

Arionta, =341=, 353, 441

Ariophanta, 301, =308=, 309, 316, 440; protective coloration, 70

Aristotle, on modified arm of polypus, 138

Artemis, 454

Arthuria, 403

Asaphis, 456

Ascoceras, 394

Ascoglossa, 11 n., 431

Ashford, C., on pulsations of heart in Helix, 26; on homing of Helix, 35; on dart-sac, 143

Asolene, 416

Aspergillum, 262, 459

Aspidelus, 329, 440

Aspidoceras, 399

Assiminea, 415

Astarte, 451

Asthenothaerus, 459

Astralium, 409

Athoracophorus, 443--see Janella

Athyris, 499, 500, 505; stratigraphical distribution, 507, 508

Atilia, 423

Atlanta, 421, 422; foot, 200

Atopocochlis, 330, 441

Atremata, 511

Atretia, distribution, 486, 487

Atrypa, 501, =502=, 505; stratigraphical distribution, 507, 508

Atrypidae, 501, 505, 508

Aturia, 393, 395

Atys, =428=, 430

Aucapitaine, H., on tenacity of life, 38

Aucella, 449

Aulopoma, 157, 304, 414; operculum, =269=

Aulosteges, 504; stratigraphical distribution, 507

Auricula, =439=, 439

Auriculella, 327, 443

Auriculidae, 17, =18=, =260=, =439=, 439; lung, 160; eyes, 186; radula, 235

Austenia, 301, 304, 440

Avellana, 430

Avicula, 254, 258, =449=, 449; eyes, 190; genital orifice, 242; A. margaritifera, 100

Aviculopecten, 450

Aviculopinna, 449

Axinus, 452

Azeca, 442

Azygobranchiata, 155, 407

Babinka, 447

Bactrites, 395

Baculites, 399

Baikalia, 290, 415

Baird, Mr., on the British Museum snail, 37

Balea, 442; B. perversa, 24, 41

Baltic, fauna of the, 12, 83, 366

Bankivia, 408

Barbatia, 448

Barleeia, 415

Barnacle, Rev. H. G., on musical sounds, produced by Mollusca, 51

Barometers, snails as, 50

Bartlettia, 452

Basilissa, 376, 408

Basommatophora, 11, 19, 181, 438

Basterotia, 451

Bateson, W., on variation in Cardium, 91; on hearing in Anomia, 196

Bathmoceras, 395

Bathydoris, 433

Bathyteuthis, 390

Batissa, 320, 453

Beddomea, 304

Beecher on phylogeny, 509

Beetles, prey on Mollusca, 58

Bela, 426; radula, =219=

Belemnites, 380

Belemnitidae, 387

Belemnosepia, 390

Bellerophon, =266=, 407

Belopetra, 380

Belopteridae, 388

Belosepia, 386, 388

Beloteuthis, 390

Bembix, 376, 408

Benedictia, 290, 415

Benthobia, 377

Benthodolium, 377

Berendtia, 441

Beudant, experiments on Mollusca, 12

Bideford Bridge and mussels, 117

Binney, Dr., on epiphragm, 28

Binneya, 341, 441

Biradiolites, 456

Birds, devour Mollusca, 56 f.

Bithynella, 289, 293, 415

Bithynia, 336, 342, 415; stomach, 239; habitat, 25

Bittium, 416

Blaesospira, 346, 351

Blandiella, 16, 414

Blanfordia, 414

Blind Mollusca, 185

Blood, 171

Bodö, land Mollusca, 24

Boeuf and French oysters, 107

Bolma, 409

Boltenia, 346

Boreofusus, radula, 221

Bornella, 433; stomach, 239

Borsonia, 426

Borus, 356–358, 441

Bourcieria, 357, 410

Bourguetia, 417

Bourguignatia, 332

Bouvier--see Fischer

Boysia, 302, 442

Brachial apparatus, types of, 500

Brachiopoda, fossil, limestone formed of, 492; shell, 493, 497; muscle scars on, 494, 501; platform, 495; synopsis of families, 503; stratigraphical distribution, 506; phylogeny and ontogeny, 509; Orders, 511

Brachiopoda, recent, 463; historical account of, 464; shell, 465; body, 469; digestive system, 471; body cavity, 472; heart, 473; excretory organs, 474; muscles, 475; nervous system, 478; reproductive system, 478; embryology, 479; habits, 482; distribution, 484; classification, 487; affinities, 487

Brachytrema, 417

Brackish-water species, 14

Branchiae, 151, 153, 164

Branchial siphon, 155, 164, 173

Braun, on self-impregnation, 44

Breathing organs--see Respiration, Branchiae

Brechites, 459

Breeding, periodicity in, 129

Broderipia, 408

Brotia, 305

Brownia, 133

Buccinanops, 423

Buccinopsis, 424; radula, 221, 222; egg-laying, 128

Buccinum, =6=, 424; radula, 217; monstrosity, =251=; breeding, 129; osphradium, =195=; spawn, =126=

Buliminus, 24, 278, 285, =295= f., 316, 331, 339, 442; protective habits, 70; B. pallidior, 38

Bulimulus, 278, 334, 339–359, 442; jaw, =211=, 233; radula, 233; variation, 87

Bulimus, 278, 342–359, =355=, 441; radula, 233; egg, =124=

Bulinus--see Isidora

Bulla, 428, 430

Bullia, =155=, 423; habits, 192; foot, 198; radula, 221

Bulloidea, 429

Burrowing Mollusca, 446

Burying propensities of Mollusca, 27, 41

Busycon, 424; money made from, 97; egg-capsules, =125=--see Fulgur

Butterell, Mr., on habits of Testacella, 52

Byssocardium, 455

Byssus gland, 201

Cadlina, 434

Cadoceras, =393=

Cadulus, 376, 445

Caecilianella, 442; habitat, 48; eyes, 186

Calcarella, 133

California, land Mollusca, 280

Calliostoma, 408; jaws, =212=

Callistochiton, 403

Callochiton, 403

Callogaza, 408

Callonia, 442

Callopoma, 409

Calma, protective coloration, 74

Calybium, 410

Calycia, 320, 442

Calycidoris, 434

Calyptraea, =248=, 412

Camaena, 305, 306, 315, =316=, 441

Cambrian, Mollusca of the, 2

Camitia, 409

Campaspe, 433

Camptoceras, =302=

Camptonyx, 278, =302=, 439

Campylaea, 285, 289 f., =293=, 441

Canal, 155

Cancellaria, 426

Canidia, 16, 305, 423

Cannibalism in snails and slugs, 32, 33

Cantharidus, 408

Cantharus, 275; radula, =222=

Caprina, 456

Caprotina, 456

Capulus, 412

Caracolus, =347=-351, 441

Carbonicola, 451

Cardiacea, 454

Cardiapoda, 421

Cardilia, 454

Cardinal plate, 500

Cardinal process, 497, 501

Cardinalia, 408

Cardinia, 451

Cardita, =273=, 451

Carditella, 451

Carditopsis, 451

Cardium, =6=, =273=, =455=, 455; C. edule, =12=, =164=; modifications, 12; variation, 84, =91=; nervous system, 207; distribution, 292, 297

Carelia, 327, 443

Carinaria, =9=, =422=, 422; foot, 200

Carinifex, 439

Carolia, 448

Cartusiana, 296

Carychium, 18, 439

Caryodes, 325, 359, 441

Casella, radula, 230

Caspia, 12, 297

Caspian Sea, fauna, 12, 297

Cassidaria, 420

Cassidula, =18=, 278, =439=, 439

Cassis, 255, 420; radula, =223=

Castalia, 344, 452

Cataulus, 157, 266, 304, 414

Caterpillars mimicking Clausilia, 68

Cathaica, 316, 441

Catinella, 443

Cavolinia, 158, 436; eyes, 186

Cecina, 414

Cenia, 432; breathing, 152

Centrodoris, 434; radula, 230

Centronella, 499, 506, 508

Cephalopoda, 378 f.; defined, 5; ink, 65; egg-laying, 127; embryo, =133=; branchiae, 168; osphradium, 195; foot, 200; nervous system, 206; jaws, 213; radula, 236

Cepolis, 349–351, 441

Cerastoma, 423

Cerastus, 331, 441

Cerata of Nudibranchs, 71, 159

Ceratites, 397, =398=; suture, =396=

Ceratodes, 357, 416

Ceres, =21=, 354, 410

Ceritella, 417

Cerithidea, 260, 417; C. obtusa, breathing, 152

Cerithiopsis, 417

Cerithium, =16=, 416

Ceromya, 458

Chaetoderma, =404=, 404; breathing organs, =154=; nervous system, =203=; radula, 217, 228

Chaetopleura, 403

Chama, 257, 272, 446, 455

Chamostrea, 458

Changes in environment, effect of, 83 f.

Chank-shell, fishery of, 100

Charis, 324, 442

Charopa, 319, 323–327, 441

Chascax, 424

Chelinodura, 430

Chelotropis, 133

Chenopus, 418

Chilidium, 498

Chilina, 19, 343, 358

Chilinidae, 439; radula, 236

Chilotrema, 441

China, use of shells in, 101

Chiropteron, 133

Chiroteuthis, 385, 391

Chiton, =8=, =153=, 403; egg-laying, 126; breathing organs, 153 f.; eyes, =188=; osphradium, 195; radula, =228=; nervous system, =203=; valves, =401=, =402=; girdle, =403=

Chitonellus, =404=, 404; valves, =401=

Chittya, 16, 348, 351, 414

Chlamydephorus, 333, 440

Chlamydoconcha, 175, 245, 453

Chlamys, 450

Chloritis, 306, 311, 319–324, 441

Chlorostoma, 408

Chlorostracia, 307

Choanomphalus, 250, 290, 439

Chondrophora, 389

Chondropoma, 346–355, =348=, 414

Chondrula, 285, =295=, 296, 442

Choneplax, 404

Chonetes, 504; stratigraphical distribution, 507, 508

Choristes, 420

Choristoceras, 398

Chorus, 423

Chromodoris, 434; jaws, =212=; radula, 230

Chrysallida, 422

Chrysodomus, 423

Chrysostoma, 409

Cingula, 415

Cingulina, 422

Cionella, 442

Circe, 454, =458=

Circulatory system, 169

Circulus, 408

Circumpolar species, 287

Cirrhoteuthis, 381, =382=

Cistella, 467, =470=, 472, 475, 476, 479, 480, 487; larvae, =481=, 483; parasite of, 485; distribution, 486; fossil, 506, 508

Cistopus, 385

Cistula, 349, 351, 355, 414

Cladohepatica, 432

Clanculus, 408

Classification, 5, 8; of Gasteropoda, 8, 11

Clathurella, 426

Clausilia, =442=, 442; mimicked by caterpillars, 68; monstrosity, 251; distribution, 285 f., =294=, 305–318, 332, 339–356; C. rugosa, 24; scalaris, 278

Clavagella, 262, 459

Clavator, 335, 359, 441

Clavatula, 426

Clavella, 424

Claviger, 329, 417

Clea, =16=, 305, 423

Clementia, 454

Cleodora, =436=, 436

Cleopatra, 294, 328, 331, 336, 416

Clessin, on duration of life, 39

Clessinia, 12, 297

Clio, =436=, 436

Cliona, enemy of oysters, 112

Clione, 158, 438

Clionopsis, 437

Clitambonites, 498, 505; stratigraphical distribution, 507, 508, 511

Clithon, 327, 410

Clydonites, 398

Clymenia, 397

Clypidella, 406

Cocculina, 408

Cochlicella acuta, 278

Cochliolepas, 77

Cochloceras, 398

Cochlodésma, 459

Cochlostyla, 124, 278, =313=, 315, 441

Cockles, use of, 101, 118

Coecum, 247, =260=, 417, =418=

Coeliaxis, 334, 442; habitat, 49

Coelocentrum, =353=, 442

Coelospira, 505, 508

Cold winter, effect on oysters, 112; on mussels, 116

Collinge, W. E., on growth and burial of shells, 41

Collisella, 405

Collisellina, 405; radula, 227

Collonia, 409

Colobocephalus, 430

Colour of arctic shells, 86

Colpodaspis, 430

Columbarium, 426

Columbella, 423; radula, =222=

Columbellaria, 420

Columbellina, 420

Columna, 328, =330=, 443

Cominella, =16=, 424

Composition of shell, 252

Concha, 463

Conchidium, 497, =498=, 500, 505; stratigraphical distribution, 507, 508, 511

Concholepas, 267, 423

Conidea, 423

Conocardium, 455

Conorbis, 426

Conus, 247, 275, 426; poisonous bite, 65; tooth, =66=; shell, =69=, =255=, 260; mimicked by Strombus, 69; prices given for rare, 121; spawn, =125=; radula, 218, =220=; operculum, =269=

Cookia, 409

Coptochilus, 314, 414

Coralliophaga, 451

Coralliophila, 75, 423

Coralliophilidae, radula, 216

Corambe, 434

Corasia, 311, 319–321

Corbicula, 15, 288, 292 f., 453

Corbis, 452

Corbula, 456

Corilla, 303

Corona, 27, 442

Coronaria, =297=

Coryda, 346–351, 441

Coryphella, 432

Cosmoceras, 399

Cowry used as money, 96

Coyote trapped by Haliotis, 57

Cranchia, 391

Crania, 464, =467=, 468, 469, 471, 472, 473, 475, 476, =477=, 487; distribution, 485; fossil, 493, 494, 504; stratigraphical distribution, 506, 507, 508, 510

Craniidae, 487, 496, 504, 508

Cranopsis, =265=, 406

Craspedochiton, 403

Craspedopoma, 298, 414

Craspedostoma, 408

Crassatella, 451

Cratena, 432

Crawling of Helix, 45

Cremnoconchus, 16, 302, 413

Crenatula, 75, 449

Crenella, 449

Crenipecten, 450

Crepidula, =248=, 257, =412=, 412; parasitic, =78=

Crepipatella, =248=, 412

Creseis, =436=, 436; eyes, 186

Crimora, 434; radula, 229

Crioceras, 247, =399=, 399

Cristigibba, 311, 319, 320, 441

Crossostoma, 408

Crucibulum, =248=, 412

Cryptochiton, 245, 371, 402, 404

Cryptochorda, 425

Cryptoconchus, 404

Cryptophthalmus, 430

Cryptostracon, 353, 441

Ctenidia, 151--see Branchiae

Ctenopoma, 346–351, 414

Cucullaea, 274, 448

Cultellus, 457

Cuma, 423

Cumingia, 453

Cuspidaria, 459; branchiae, 168

Cuvierina, =436=, 436

Cyane, 410

Cyathopoma, =247=, 268, 314, 338, 414

Cyclas, 453; veliger, =132=; ova, 146; otocyst, =197=; C. cornea, thread-spinning, 29; distribution, 282

Cyclina, 454

Cyclobranchiata, 156

Cyclocantha, 409

Cyclomorpha, 414

Cyclonassa, 423

Cyclonema, 409

Cyclophoridae, origin, 21

Cyclophorus, 302, =306=-319, 329–334, 344, 352–358, 414; jaws, =212=; radula, =21=

Cyclostoma, 328, 331–338, =414=, 414; stomach, 239; vision, 184; osphradium, 195; nervous system, =205=; C. elegans, 287, 288

Cyclostomatidae, origin, 21; radula, 224; gait, 199

Cyclostrema, 408

Cyclosurus, =247=, 337, 414

Cyclotopsis, 338, 414

Cyclotus, 296, 319, 320, 414

Cylichna, =428=, 430; radula, 215

Cylindrella, =247=, =260=, 278, 343–355, =348=, 442; monstrosity, 251, =252=

Cylindrellidae, radula, 233, =234=

Cylindrites, 430

Cylindrobulla, 430

Cylindromitra, 425; radula, 222

Cymbium, 255, 367, 425; radula, =221=

Cymbulia, 437

Cymbuliopsis, 437

Cynodonta, 424

Cyphoma, 419

Cypraea, =178=, 419; prices given for rare, 122; mantle-lobes, 177, =178=; radula, =224=; shell, =255=, 260, =261=; C. moneta, 96

Cypraecassis, 420

Cypraedia, 419

Cypraeovula, 419

Cyprimeria, 454

Cyprina, 451

Cyrena, 15, 453; distribution, 285, 294

Cyrenella, 453

Cyrtia, 505; stratigraphical distribution, 507, 508

Cyrtoceras, 394

Cyrtodaria, 457

Cyrtodonta, 452

Cyrtolites, 407

Cyrtonotus, 448

Cyrtotoma, 414

Cysticopsis, 346–351, 441

Cystiscus, 425

Cystopelta, 325, 326, 440

Cytherea, =454=, 454

Dacrydium, 449

Daedalochila, 441

Dall, W. H., quoted, 35; on branchiae, 164

Damayantia, 440

Daphnella, 426

Darbyshire, R. D., on tenacity of life, 39

Dardania, 415

Dart-sac, 142

Daudebardia, =289=, 292 f., 440

Davidsonia, 505, 508

Dawsonella, 410

Dayia, 505, 508

Decapoda, 385 f.

Decollation, 260

Deep-sea Mollusca, 374

De Folin, experiment on Cyclostoma, 157

Deianira, 410

Delage, experiments on otocysts, 197

Delphinula, 409

Deltidium, 499

Dendronotus, 433; protective coloration, 72; habits, 51

Dentalium, =6=, =444=, 445; used as money, 97; veliger, =131=; radula, =228=

Dentellaria, =350=-355, 441; aperture, =63=

Desert species, 25, 85

Deshayesia, 411

Desmoulea, 423

Development of fertilised ovum, 130 f.

Dexiobranchaea, 437

Diadema, 414

Diala, 415

Dialeuca, 441

Diaphora, 314

Diaphorostoma, 412

Diastema, 418

Diastoma, 417

Diaulula, 434

Dibaphus, 425

Dibranchiata, 380; eye, 183; nervous system, 207

Diceras, 269, 455

Didaena, =12=, 297, 455

Differences of sex, 133

Dignomia, 511

Digonopora, 134, 144

Diloma, 408

Dimorphoptychia, 410

Dimya, 450

Dinobolus, 504, 508

Dinoplax, 403

Ditocardia, 9, 170, 405 f.

Diplodonta, 452

Diplommatina, 302–327, 413

Diplomphalus, 322, 323, 440

Diplopoma, 346, 351, 414

Dipsaccus, 424

Dipsas, 307

Discina, 464, 468, 471, 475, 487; distribution, 485; fossil, 493, 504; stratigraphical distribution, 506, 508

Discinidae, 487, 496, 504, 508, 511

Discinisca, 487, 510; distribution, 485, 486

Discites, 395

Discodoris, 434

Discosorus, 394

Distortio, 255--see Persona

Ditropis, 312, 314, 414

Docoglossa, 227, 405

Dolabella, =428=, 431

Dolabrifer, 431

Dolium, 419; acid secretion, 237

Donax, 269, 446, 453

Dondersia, 404

Dorcasia, 333, 441

Doridium, 430

Doridunculus, 434; radula, 229

Doriopsis, 434

Doris, breathing organs, =159=; radula, 230

Dorsanum, 423

Dosidicus, 390

Dosinia, 454

Doto, 433; protective coloration, 71

Dreissensia, =14=, 123, 452; hibernation, 26; singular habitat, 48; veliger, =132=, 146; eyes, 192

Dreissensiomya, 452

Drepania, 434

Drillia, 426

Drymaeus, 356, 442

Dryptus, 356, 441

Durgella, 301, 304, 440

Dwarf varieties, 88

Dybowskia, 290

Eastonia, 454

Eburna, =267=, 424; radula, =220=

Ecardines, 466; muscles, 476; fossil, 493; families, 487, 503, 508

Eccyliomphalus, 413

Echinospira, 133

Edentulina, 338

Egg-laying of Arion, =42= f.; of Mollusca generally, 123

Eglisia, 411

Eider-duck, shells used by, 102

Elaea, 322, 440

Elasmoneura, 411

Eledone, =385=, 385; radula, 236

Elizia, 456

Elysia, 432; protective coloration, 73; breathing, 152; radula, 217, =230=, =432=

Emarginula, =265=, 406

Embletonia, 429

Emmericia, 415

Ena, 296, 442

Enaeta, 425

Endoceras, 394

Endodonta, 325, 334, 441

Engina, 424

Enida, 408

Ennea, 298, 302, 306, 309, 314, 316, 328–337, =440=, 440; habits, 54; E. bicolor, 279

Enoplochiton, =403=, 403

Enoploteuthis, 391

Ensis, 457

Entocolax, 77, 79, 152

Entoconcha, 77, 79, 152, 216

Entovalva, 77, 82

Ephippodonta, 453; commensal, =81=

Epidromus, 420

Epiphragm, 26, 27 f.

Epipodia, 427

Erato, 419

Eremophila, 294

Ergaea, =248=, 412

Erinna, 327, 439

Erosion, 276

Ervilia, 454

Erycina, 453

Escargotières, 119

Estria, 329, 440

Estuarine species, 14

Ethalia, 409

Eucalodium, 260, 353, 442

Euchelus, 408

Euchrysallis, 420

Eudioptus, 442

Eudoxochiton, 403

Euhadra, 316, 318, 441

Eulamellibranchiata, 451; gill, =166=, 167

Eulima, 422; parasitic, 77, =79=

Eulimella, 250, 422

Eulota, 296, 441

Euomphalus, 247, 413

Euplecta, 440

Eupleura, 423

Euplocamus, 434

Eurybia, 438

Eurycampta, 346–351

Eurycratera, 349, 351, 441

Eurystoma, 304

Eurytus, 442

Euthria, 424

Euthyneura, 203

Eutrochatella, 347–351, =348=, 410

Exploring expeditions, 362

Eye in Mollusca, 181 f.

Facelina, 432

Fasciolaria, 424; radula, =221=

Fastigiella, 416

Favorinus, 432

Fenella, 415

Fertilised ovum, development, 130 f.

Ferussacia, 291, 293, 297 f., 442

Fiji islanders, use of shells, 98

Filibranchiata, 448; gill, =166=

Fiona, 432; radula, 217

Firoloida, 421

Fischer and Bouvier, on breathing of Ampullaria, 158

Fischeria, 15, 328, 453

Fish devour Mollusca, 59

Fissurella, =265=, 406; breathing organs, =153=; apical hole, 156; nervous system, 204; radula, 227; growth, =261=

Fissurellidaea, 406

Fissuridea, 406

Fissurisepta, 406

Fistulana, 262, 457

Flabellina, 432

Fluminicola, 415

Folinia, 415

Food of Mollusca, 30 f.; Mollusca as food, 102 f.

Foot, 198; in classification, 5

Forel, on deep-water Limnaea, 162

Formation of shell, 255

Fortisia, 429

Fossarina, 413

Fossarulus, 302, 415

Fossarus, 413

Fourth orifice in mantle, 174

Fresh-water species living in sea, 12; frozen hard, 24

Frogs and toads devour Mollusca, 58

Fruticicola, 285, 290, 316, 318, 441

Fruticocampylaea, 296

Fryeria, 434

Fulgur, =249=, 424

Fusispira, 420

Fusus, 262, 424

Gadinia, =152=, 431; breathing, 18, 151; classification, 19; radula, 217, =230=

Gain, W. A., quoted, 32, 33, 39; on taste of Mollusca, 179

Galatea, 15, 328, 336, 453

Galeomma, 175, 453

Galerus, =248=, 412; egg-capsules, 125

Garstang, W., on protective and warning coloration, 73

Gaskoin, on tenacity of life, 38; on egg-laying, 42

Gassies, on hybrid union in snails, 130

Gasteropoda, on classification, 8, 11, 400 f.

Gastrana, 453

Gastrochaena, 457; habits, 64

Gastrodonta, 440

Gastropteron, 245, 430

Gaza, 376, 408

Gena, 246, 408

Genea, 424

Genotia, 426

Geomalacus, =160=, 288, 291, 441; protective coloration, 70

Geomelania, 16, 348, 351, 414

Georgia, 331, 414

Georissa, 318, 410

Geostilbia, 338, 442

Gerontia, 441

Gerstfeldtia, 290

Gibbula, 408

Gibbus, 328–=338=, =440=, 440

Gillia, 415

Gills--see Branchiae

Girasia, 301, 304, 440

Glandina, =54=, =178=, 278, 292 f., 339–355, 440; radula, 231, =232=; habits, 53

Glands, germ, 134, 140; nidamental, 136

Glassia, 501, 505

Glaucomya, 320, 454

Glaucus, 429, 432

Gleba, 437

Glessula, 301, 309, 310, 333, 442

Glochidium, =147=

Glomus, 448

Glossoceras, 394

Glossophora, 7

Glottidia, distribution, 485, 487

Glycimeris, 457

Glyphis, 406

Glyptostoma, 341, 441

Gomphoceras, 394, =395=

Gonatus, 391

Goniatites, 397, =398=

Goniobasis, 341, 417

Goniodoris, 434; protective coloration, 73; radula, 229

Goniomya, 458

Gonostoma, 291, 316, 441

Goniostomus, 442

Grammysia, 459

Grateloupia, 454

Great Eastern and mussels, 116

Greenhouses, slugs in, 35

Green oysters, 108

Gresslya, 458

Growth of shell, 40, 257

Guesteria, 440

Guildfordia, 409

Guivillea, 186, 376, 425

Gulls and Mollusca, 56

Gundlachia, 19, 325, 345, 352, 359, 439

Gymnoglossa, 216, 225, 422

Gymnosomata, 437

Gyroceras, 247, 395

Gyrotoma, 417

Hadra, 306, 315, 319–325, =322=, 441

Hadriania, 423

Haemoglobin, 171

Hainesia, 336, 414

Halia, 366, 426

Haliotinella, 431

Haliotis, =266=, 407; and coyote, 57; holes of, 156; osphradium, 195; epipodium, 199; nervous system, 204; radula, 215, 226

Halopsyche, 159, =438=, 438

Haminea, =428=, 430; protective coloration, 73

Hamites, 399

Hamulina, 399

Hanleyia, 403

Hapalus, 331, 442

Harpa, radula, 425, 216, 221; self-mutilation, 45

Harpagodes, 418

Harpoceras, 399

Harvella, 454

Hatching of eggs, 43

Hazay, on duration of life, 39; on variation in Limnaea, 93

Hearing powers of Mollusca, 196

Heart, in classification, 9; action during hibernation, 26; and branchiae, =169=

Hectocotylus arm, 137 f.

Helcion, 405; protective coloration, 69

Helcioniscus, 405

Hele, F. M., on Hyalinia, 33; on Stenogyra, 34

Helicarion, 309, 316, 325, 332, 440; radula, 232; habits, 45, 67

Helicidae, radula, 232, =234=

Helicina, 305, 306, 316–327, 338–358, 410; origin, =21=; exterminated by cold, 24

Helicophanta, 335, =336=, =441=, 441

Heligmus, 449

Helix, 441; toothed aperture, 63; protective coloration, 70; variation, 87; carbonic acid, 163; eye, =181=, =183=; food, 179; smell, 194; jaw, =211=; distribution, 285; tenacity of life, 37; breeding, 129

Helix alternata, =340=; angulata, =350=; aperta, 38, 39, 51, =293=; arbustorum, bathing, 23; caperata, variation, 89; cereolus, =340=; cicatricosa, =316=; crenilabris, 45; delphinuloides, =297=; desertorum, 37, 38, 70, 294; fidelis, =341=; haemastoma, habits, 70; harpa, 287; hortensis, =10=, 279; pulsations, 26; epiphragm, 28; rock-boring, 49; dart, =143=; imperator, =347=; habits, 45; laciniosa, =297=; lactea, 25, 38, 42, 279; lima, =350=; muscarum, =347=; nemoralis, 38, =180=; niciensis, =292=; nux denticulata, =350=; palliata, =340=; pisana, 25; habits, 33; pomatia, 25, 34, 40; eye, =181=; pomum, =322=; pulchella, 279; richmondiana, =322=; rosacea, =259=; rostrata, =347=; rota, =314=; rufescens, pulsations, 26; similaris, 279; souverbiana, =336=, =441=; strigata, =293=; tristis, habits, 49; turricula, =297=; Veatchii, 38; Waltoni, =304=; Wollastoni, =297=; zonata, =293=

Helix aspersa, homing, 35; smell, 36; duration of life, 39; growth, 40; strength, 45; boring rock, 50; variation, 87, 89; eaten, 119; hybrid union, 130; generative organs, 140 f., =141=; dart-sac, =143=; pulmonary chamber, 160; radula, 217; alimentary canal, =237=; monstrosities, 251, =252=; growth, 258; distribution, 279, 289

Hemiarthrum, 403

Hemicardium, 455

Hemidonax, 453

Hemifusus, 424

Hemipecten, 450

Hemiplecta, 310, 316, 319, 321, 440

Hemisepius, 389

Hemisinus, 357, 417

Hemitoma, =265=

Hemitrichia, 314

Hemitrochus, 346–351, 441

Hemphillia, 245, 341, 441

Hercoceras, 395

Herdman, Prof. W. A., on cerata of Nudibranchs, 71 f.; experiments on taste of Nudibranchs, 72; on Littorina rudis, 151 n.

Hermaea, 432; protective coloration, 73

Hermaphrodite Mollusca, 134, 140, 145

Hermit-crabs, shells used by, 102

Hero, 432

Heterocardia, 454

Heterodiceras, 455

Heteropoda, 9, 420 f.; radula, 228; foot, 200

Heudeia, 316, 410

Hexabranchus, 434

Hibernation, 25, 163

High altitudes, Mollusca living at, 24

Himella, 15

Hindsia, 424

Hindsiella, 453

Hinge area, 493, 498

Hinge, in bivalves, 272

Hinnites, 257, 450

Hipponyx, 248, 412

Hippopus, 455

Hippurites, =455=, 456

Histiopsis, 391

Histioteuthis, 391

Holcostoma, 417

Holohepatica, 433

Holopella, 411

Holospira, 339, 353, 442

Holostomata, 156

Homalogyra, 413; radula, 223

Homalonyx, 245, =343=-358, 443

Homing powers of Mollusca, 34

Homorus, 330–337, 443

Hoplites, 399

Hoplopteron, 422

Horea, 332

Horiostoma, 409

Hot springs, Mollusca living in, 25

Huronia, 394

Hyalaea, =10=, 436

Hyalimax, 245, 305, 306, 338, 443

Hyaline stylet, 240

Hyalinia, 440; pulsations, 26; food, 33; smell, 194; dart, =143=; radula, 232, =234=; distribution, 287 f., 318, 340–357; H. alliaria, 279; smell, 194; cellaria, 279; Draparnaldi, 33

Hyalocylix, 437

Hyalosagda, 352

Hybocystis, =305=, 309, 414

Hybridism, 129

Hydatina, 430; radula, =231=

Hydrobia, 325, 332, 415; H. ulvae, egg-laying, 128

Hydrocena, 298, 410; radula, 226

Hymenoptera build in dead shells, 102

Hypobranchaea, 434; radula, 230

Hypotrema, 448

Hypselostoma, 248, =302=, 305, 314, 442

Hyria, 344, 452

Hystricella, 297

Ianthina, 360, =126=, 411; egg-capsules, 125; eyes, 186; radula, =224=

Iapetella, 385

Iberus, 285–=293=, =297=, 441

Ichthyosarcolites, 456

Idalia, =179=, 429, 434; radula, 229, 230

Idas, 449

Idiosepion, 389

Illex, 390

Imbricaria, 425; radula, =221=

Imperator, 409

Indians of America, use of shells, 100

Infundibulum, 408

Inioteuthis, 389

Ink-sac, =241=

Inoceramus, 449

Insects eaten by Mollusca, 32

Insularia, 319, 320

Intestine, 241

Io, =16=, 340, 417

Iopas, 423

Iphigenia, 15, 453

Iravadia, 305, 415

Iridina, 294

Irus, 297

Isanda, 409

Ischnochiton, 403

Isidora, 298, 320–327, 333, 336, 359, 439

Ismenia, 404

Isocardia, 269, =451=, 451

Isodonta, 453

Isomeria, 343, 356, 441

Issa, 434

Jamaicia, 414

Janella, =161=, 443; pulmonary orifice, =161=

Janellidae, radula, 234; distribution, 321–326

Janus, 432

Japonia, 318

Jaws, 210

Jeanerettia, 346–351, 441

Jeffreys, Dr., on Limnaea, 34; on Neptunea, 193

Jeffreysia, 415; radula, 223

Jorunna, protective coloration, 73

Jouannettia, 457

Jullienia, 307, 415

Jumala, 424

Kaliella, 301, 304, 310, 314–317, 335, 440

Kalinga, 434

Kashmir, land Mollusca, 280

Katherina, 403

Kelletia, 424

Kellia, 453

Kellyella, 452

Kidneys, 242

King, R. L., on smell in bivalves, 195

Kingena, 506, 508

Kitchen-middens, 104

Koninckella, 505; stratigraphical distribution, 507, 508

Koninckina, 505; stratigraphical distribution, 507, 508

Koninckinidae, 501, 505, 508

Kutorgina, 504; stratigraphical distribution, 506, 508; embryonic shell, 509

Labial palps, 210

Labyrinthus, 342, 353–357, 441; aperture, =63=

Lacaze-Duthiers on Testacella, 52 f.; on smell in Helix, 194

Lacuna, 413

Lacunopsis, 332

Lagena, 424

Lagochilus, 309, 316–319, 414

Lamellaria, 245, 411; habits and protective coloration, 74; parasitic, 78; radula, 223

Lamellidoris, 434; radula, 229, 230, =231=

Lampania, 417

Land Mollusca, origin, 11 f.

Lanistes, 249, 294, 328, 331, 416

Lankester, Prof. E. Ray, on shell-gland, 132; on haemoglobin, 171

Lantzia, 278, 338, 439

Laoma, 441

Larina, 302, 417

Larvae of Pelecypoda, 7; of insects resembling Mollusca, 67 f.

Lasaea, 453

Latia, 19, 326, 439

Latiaxis, 423

Latirus, 424

Latter, O. H., on Glochidium, 147

Layard, E. L., on self-burying Mollusca, 41; on sudden appearance of Stenogyra, 47; on Coeliaxis, 49; on Rhytida and Aerope, 54

Leda, 447

Leia, 348–351, 442

Leila, 344, 452

Leonia, 414

Lepeta, 405

Lepetella, 405

Lepetidae, radula, 227

Lepidomenia, 404; radula, 229

Leptachatina, 327

Leptaena, 500, 501, 502, =503=, 505; stratigraphical distribution, 507, 508

Leptaxis, 441

Leptinaria, 357, 358, 442

Leptochiton, 403

Leptoconchus, 75, 423

Leptoloma, 348, 351

Lepton, 453; parasitic, 77; commensal, 80; mantle-edge, 175, 178

Leptoplax, 403

Leptopoma, 316, 319, 338, 414

Leptoteuthis, 390

Leptothyra, 409

Leroya, 331

Leucochila, 442

Leucochloridium, =61=

Leucochroa, =292=, 295, 441

Leuconia, 439

Leucotaenia, 335, 359, 441

Leucozonia, 64, =424=, 424

Levantina, 295

Libania, 295

Libera, 327, 441; egg-laying, 128

Libitina, 451

Licina, 414

Life, duration of, in snails, 39

Ligament, 271

Liguus, 349, 351, 442

Lima, 178, =179=, 450; habits, 63

Limacidae, radula, 232

Limacina, 59, 249, =436=, 436

Limapontia, 429, 432; breathing, 152

Limax, 245, 440; food, 31, 179; variation, 86; pulmonary orifice, 160; shell, 175; jaw, =211=; radula, 217; distribution, 285, 324; L. agrestis, eats May flies, 31; arborum, slime, 30; food, 31; flavus, food, 33, 36; habits, 35, 36; gagates, 279, 358; maximus, =32=, =161=; eats raw beef, 32; cannibalism, 32; sexual union, 128; smell, 193 f.

Limea, 450

Limicolaria, 329–332, 443

Limnaea, 439; self-impregnation, 44; development and variation, 84, 92, 93; size affected by volume of water, 94; eggs, 124; sexual union, 134; jaw, 211; radula, 217, =235=; L. auricularia, 24; glutinosa, sudden appearance, 46; Hookeri, 25; involuta, 82, 278, 287; peregra, =10=, =180=; burial, 27; food, 34, 37; variation, =85=; distribution, 282; palustris, distribution, 282; stagnalis, food, 34, 37; variation, =85=, =95=; circum-oral lobes, 131; generative organs, =414=; breathing, 161; nervous system, =204=; distribution, 282; truncatula, parasite, 61; distribution, 282

Limnocardium, 455

Limnotrochus, 332, 415

Limopsis, 448

Limpet-shaped shells, 244

Limpets as food for birds, 56; rats, 57; birds and rats caught by, 57; as bait, 118

Lingula, 464, 467, 468, 471, =472=, 473, 475, 477, 478, 487; habits, =483=, 484; distribution, 485; fossil, 493, =494=, 503; stratigraphical distribution, 506, 508, 510, 511

Lingulella, 493, 503; stratigraphical distribution, 506, 508, 511

Lingulepis, 503, 511

Lingulidae, 485, 487, 496, 503, 508

Linnarssonia, 504; stratigraphical distribution, 506, 508

Lintricula, 426

Liobaikalia, 290

Liomesus, 424

Lioplax, 340, 416

Liostoma, 424

Liostracus, 442

Liotia, 408

Liparus, 324, 359, 441

Lissoceras, 399

Lithasia, 340, 417

Lithidion, 414

Lithocardium, 455

Lithodomus, 449

Lithoglyphus, 294, 296, 297, 415

Lithopoma, 409

Lithotis, 302, 443

Litiopa, 30, 361, 415

Littorina, 413; living out of water, 20; radula, =20=, 215; habits, 50; protective coloration, 69; egg-laying, 126; hybrid union, 130; monstrosity, =251=, =252=; operculum, =269=; erosion, 276; L. littorea, in America, 374; obtusata, generative organs, =135=; rudis, 150; Prof. Herdman’s experiments on, 151 n.

Littorinida, 415

Lituites, 247, 395

Liver, 239; liver-fluke, 61

Livinhacea, 333, 359, 441

Livona, 408; radula, 226; operculum, =268=

Lloyd, W. A., on Nassa, 193

Lobiger, 432

Lobites, 397

Loligo, 378–389; glands, 136; modified arm, 139; eye, =183=; radula, 236; club, =381=; L. punctata, egg-laying, 127; vulgaris, larva, 133

Loligopsis, 391

Loliguncula, 390

Loliolus, 390

Lomanotus, 433

Lophocercus, 432

Lorica, 403

Lowe, E. J., on growth of shell, 40

Loxonema, 417

Lucapina, 406

Lucapinella, 406

Lucerna, 441

Lucidella, 348–351, 410

Lucina, =270=, 452

Lucinopsis, 454

Lung, 151, 160

Lunulicardium, 455

Lutetia, 452

Lutraria, 446, 456

Lychnus, 442

Lyonsia, 458

Lyonsiella, 458; branchiae, 168

Lyra, stratigraphical distribution, 507

Lyria, 425

Lyrodesma, 447

Lysinoe, 441

Lytoceras, 398

Maackia, 290

Macgillivrayia, 133

Machomya, 458

Maclurea, 410

Macroceramus, 343–353, 442

Macroceras, 440

Macrochilus, 417

Macrochlamys, 296, 299, 301 f., 310, 316–322, 440

Macrocyclis, 358, =359=, 442

Macron, 424

Macroön, 441

Macroscaphites, 247, =399=, 399

Macroschisma, =265=, 406

Mactra, 271, 446, 454

Macularia, 285, 291, =292= f., 441

Magas, 506; stratigraphical distribution, 507, 508

Magellania, 500

Magilus, =75=, 423

Mainwaringia, 302

Malaptera, 418

Malea, 419

Malletia, 447

Malleus, 449

Mangilia, 426

Mantle, 172 f., =173=; lobes of, 177

Margarita, 408; radula, =225=

Marginella, 425; radula, 221

Mariaella, 314, 338, 440

Marionia, 433

Marmorostoma, 409

Marrat, F. P., views on variation, 82

Marsenia, 133

Marsenina, 411

Martesia, 305, 457

Mastigoteuthis, 390

Mastus, 296, 442

Matheronia, 455

Mathilda, 250, 417

Maugeria, =403=

Mazzalina, 424

Megalatractus, 424

Megalodontidae, 451

Megalomastoma, 344, 414

Megalomphalus, 416

Megaspira, 358, 442

Megatebennus, 406

Megerlia, distribution, 486, 487

Meladomus, 249, 328, 331, 416

Melampus, =18=, 199, 250, =439=, 439

Melanatria, 336

Melania, =276=, =417=, 417; distribution, 285, 292 f., 316 f., 324, 336

Melaniella, 442

Melaniidae, origin, 17

Melanism in Mollusca, 85

Melanopsis, 417; distribution, 285, 291, 292 f., 323, 326

Melantho, 340, 416

Melapium, 424

Meleagrina, 449

Melia, 348

Melibe, 432

Melongena, 424; radula, =220=; stomach, =238=

Merica, 426

Merista, 505, 508

Meroe, 454

Merope, 327

Mesalia, 417

Mesembrinus, 356, 442

Mesodesma, 454

Mesodon, =340=, 441

Mesomphix, 340, 440

Mesorhytis, 377

Meta, 423

Metula, 424

Meyeria, 424

Miamira, 434

Microcystis, 323, 324, 327, 338, 440

Microgaza, 408

Micromelania, 12, 297

Microphysa, protective habits, 70

Microplax, 403

Micropyrgus, 415

Microvoluta, 425

Middendorffia, 403

Milneria, 451

Mimicry, 66

Minolia, 408

Mitra, 425; radula, 221

Mitrella, 423

Mitreola, 425

Mitrularia, =248=, 412

Modiola, 446, 449; habits, 64; genital orifice, 242

Modiolarca, 449

Modiolaria, 449; habits, 78

Modiolopsis, 452

Modulus, 417

Monilia, 408

Monkey devouring oysters, 59

Monoceros, 423

Monocondylaea, 452

Monodacna, 12, 297, 455

Monodonta, 408, =408=; tentaculae, =178=

Monogonopora, 134, 140

Monomerella, 496, 504

Monopleura, 456

Monotis, 449

Monotocardia, 9, 170, 411

Monstrosities, 250

Montacuta, 452; M. ferruginosa, commensal, 80; substriata, parasitic, 77

Mopalia, 403

Moquin-Tandon, on breathing of Limnaeidae, 162; on smell, 193 f.

Moreletia, 440

Morio, 420

Mormus, 356, 442

Moseley, H. N., on eyes of Chiton, 187 f.

Moussonia, 327

Mouth, 209

Mucronalia, 422

Mucus, use of, 63

Mulinia, =272=

Mülleria, 344, 452

Mumiola, 422

Murchisonia, 265, 407

Murchisoniella, 422

Murex, 423; attacks Arca, 60; use of spines, 64; egg-capsules, 124; eye, =182=; radula, =220=; shell, =256=

Musical sounds, 50

Mussels, cultivation of, 115; as bait, 116; poisonous, 117; on Great Eastern, 116

Mutela, 294, 328, 331, 336, 452

Mutyca, 425

Mya, 271, 275, =446=, 456; stylet, 240; M. arenaria, variation, 84

Myacea, 456

Myalina, 449

Mycetopus, 307, 316, 344, 452

Myochama, =458=

Myodora, 458

Myophoria, 448

Myopsidae, 389

Myrina, 449

Myristica, 424

Mytilacea, 448

Mytilimeria, 458

Mytilops, 452

Mytilopsis, 14

Mytilus, 258, 449; gill filaments, =166=, 285; M. edulis, =14=, =165=; attached to crabs, 48, 78; pierced by Purpura, =60=; Bideford Bridge and, 117; rate of growth, 258; stylet, 240

Myxostoma, 414

Nacella, 405

Naiadina, 449

Nanina, 278, 300 f., 335, 440; radula, 217, 232

Napaeus, 296–299, 316, 442

Naranio, 454

Narica, 412

Nassa, 423; egg-capsules, =126=; sense of smell, 193

Nassodonta, 423

Nassopsis, 332

Natica, =246=, 263, 411; spawn, =126=; operculum, =268=

Naticopsis, 409

‘Native’ oysters, 106

Nausitora, 15

Nautiloidea, 393

Nautilus, 254, =392=, 395; modified arms, 140; eye, =183=; nervous system, 206; radula, 236; kidneys, 242

Navicella, 267, 268, 324, 327, 410; origin, =17=

Navicula, =358=, 442

Navicula (Diatom), cause of greening in oysters, 108

Nectoteuthis, 389

Neda, 431

Nematurella, 12, 297

Nembrotha, 434

Neobolus, 504

Neobuccinum, 424

Neocyclotus, 357, 358

Neomenia, =8=, 133, 216, 228, =404=, 404; breathing organs, =154=; nervous system, =203=

Neothauma, 332

Neotremata, 511

Neptunea, 252, 262, 423; egg-capsules, =126=; capture, 193; monstrosity, =251=

Nerinea, 417

Nerita, =17=, 410; N. polita used as money, 97

Neritidae, 260, 410; radula, =226=

Neritina, =256=, 410; origin, 16, =17=, =21=; egg-laying, 128; eye, 181; distribution, 285, 291 f., 324, 327; N. fluviatilis, habitat, 12, 25

Neritoma, 410

Neritopsis, 409; radula, 226; operculum, =269=

Nervous system, 201 f.

Nesiotis, 357, 442

New Zealanders, use of shells, 99

Nicida, 413

Ninella, 409

Niphonia, 408

Niso, 422

Nitidella, 423

Nodulus, 415

Notarchus, 431

Nothus, 358, 442

Notobranchaea, 438

Notodoris, 434

Notoplax, 403

Novaculina, 305

Nucula, 254, 269, =273=, 447

Nuculidae, otocyst, 197; foot, 201

Nuculina, 448

Nudibranchiata, 432; defined, 10; protective and warning colours, 71 f.; breathing organs, 159

Nummulina, 295

Nuttallina, 403

Obba, 311, 315, 441

Obbina, 306, 311, 312, =314=, 319

Obeliscus, 442

Obolella, 496, 504; stratigraphical distribution, 506, 508

Obolidae, 496, 504, 508

Obolus, 504, 508; embryonic shell, 509

Ocinebra, 423

Octopodidae, hectocotylised arm, 137, 139, =140=

Octopus, =379=-386; egg-capsules, =127=; vision, 184; radula, =236=; crop, 238

Ocythoe, 384; hectocotylus, =138=

Odontomaria, 407

Odontostomus, =358=, =442=

Odostomia, 250, 422; parasitic, 78

Oesophagus, 237

Ohola, 434

Oigopsidae, 390

Oldhamina, 506, 508

Oleacina, habits, 55

Oliva, =199=, =255=, 275, =425=, 426

Olivancillaria, 426

Olivella, 260, 267, 426; O. biplicata as money, 97

Olivia, 408

Omalaxis, 413

Omalonyx, habitat, 23

Ommastrephes, =6=, 378, 390

Ommatophores, 180, 187

Omphalotropis, 306, 309, 316, 324, 327, 338, 414

Onchidiella, 443

Onchidiidae, 245; radula, 234; anus, 241

Onchidiopsis, 411

Onchidium, 443; breathing, 163; eyes, 187

Onchidoris, radula, 230

Oniscia, 420

Onoba, 415

Onychia, 390

Onychoteuthis, 390; club, =386=

Oocorys, 420

Oopelta, 329, 440

Opeas, 442

Operculum, 267 f.

Ophidioceras, 247, 395

Ophileta, 413

Opis, 451

Opisthobranchiata, 427; defined, 9; warning, etc., colours, 71 f.; generative organs, 144; breathing organs, 158; organs of touch, 178; parapodia, 199; nervous system, 203; radula, 229

Opisthoporus, =266=, 300, 314–316, 414

Opisthostoma, 248, =309=, 413

Oppelia, 399

Orbicula, =464=

Orbiculoidea, 504, 510

Orders of Mollusca, 5–7

Organs of sense, 177

Origin of land Mollusca, 11 f.

Ornithochiton, 403

Orphnus, 356, 441

Orpiella, 440

Orthalicus, 342–358, =355=, 442; habits, 27; variation, 87; jaw, =211=; radula, 233, =234=

Orthis, 505; stratigraphical distribution, 506, 507, 511

Orthoceras, =394=, 394

Orthonota, 457

Orthothetes, 505; stratigraphical distribution, 507, 508

Orygoceras, 247

Osphradium, 194 f.

Ostodes, 327

Ostracotheres, 62

Ostrea, 252, 258, 446, 449; intestine, 241

Otina, 18, 439

Otoconcha, 326, 440

Otocysts, 196 f., =197=

Otopleura, 422

Otopoma, 331, 338, 414

Otostomus, 353, 442

Ovary, 135

Ovoviviparous genera, 123

Ovula, 419; protective coloration, 70, 75; radula, 80, 224; used as money, 97

Ovum, development of fertilised, 130

Oxychona, 358

Oxygyrus, 422; foot, 200

Oxynoe, 432; radula, 230

Oyster-catchers, shells used by, 102

Oyster, cultivation, 104–109; living out of water, 110; enemies, 110 f.; reproduction, 112 f.; growth, 114; cookery, 114; poisonous oysters, 114; vision, 190

Pachnodus, 329–335, 441, 442

Pachybathron, 425

Pachychilus, 354

Pachydesma crassatelloides, money made from, 97

Pachydomidae, 451

Pachydrobia, 307, 415

Pachylabra, 416

Pachyotus, 334, =336=, =355=, 358, 441

Pachypoma, 409

Pachystyla, 337, 440

Pachytypus, 451

Padollus, 407

Palaearctic region, 284 f.

Palaeoneilo, 447

Palaeosolen, 457

Palaina, 327, 413

Palio, 434

Pallial line and sinus, 270

Pallifera, 340, 440

Palliobranchiata, 464

Paludina, 416; penis, 136; eye, 181; vision, 184; P. vivipara, 24--see also Vivipara

Paludomus, 332, 336, 338, 417

Panama, Mollusca of, 3

Panda, 322, 325, 335

Pandora, 458

Papuans, use of shells, 99

Papuina, 309, 319–324, 441

Paramelania, 332

Paramenia, 404

Parasitic worms, 60 f.; Mollusca, 74 f.

Parastarte, 451

Parkinsonia, =398=

Parmacella, 245, 291, 294 f., 438 n., 440; radula, 232; shell, 175

Parmacochlea, 322, 326, 440

Parmarion, 309, 440

Parmella, 326, 440

Parmophorus, 406

Parthena, 349–352, =350=, 441

Parts of univalve shell, 262; bivalve, 269

Partula, 319–327, =326=, 442; radula, 233

Paryphanta, 321, 325, 440

Paryphostoma, 415

Passamaiella, 332

Patella, 405, 464; as food, 56 f.; eye, =182=; radula, =214=, 215, =227=; crop, 238; anus, 241; kidneys, 242; shell, 262; P. vulgata, veliger, =132=; breathing organs, etc., 156, =157=

Patelliform shell in various genera, 19

Paterina, 509, 510, 511

Patinella, radula, 227

Patula, 297, 298, 318–338, =340=, 441

Paxillus, 413

Pearl oysters, 100

Pecten, 446, =450=, 450; organs of touch, 178; ocelli, =191=; flight, 192; nervous system, =206=; genital orifice, 242; ligament, 271

Pectinodonta, 405; radula, 227

Pectunculus, 448

Pedicularia, 75, 419; radula, 224

Pedinogyra, 319, 322, 442

Pedipes, =18=, 199, =439=, 439

Pedum, 450

Pelagic Mollusca, 360

Pelecypoda, 7, 445; development, 145; generative organs, 145; branchiae, =166–169=; organs of touch, 178; eyes, 189 f.; foot, 201; nervous system, 205

Pella, 333

Pellicula, 352, 442

Peltoceras, 399

Pentadactylus, 423

Peraclis, 436

Pereiraea, 418

Perideris, 328–330, 443

Periodicity in breeding, 129

Periophthalmus, 187

Periostracum, 275

Periploma, 459

Perisphinctes, 399

Perissodonta, 418

Perissolax, 424

Peristernia, 424

Perna, 449; ligament, 271

Pernostrea, 449

Peronaeus, 358, 442

Peronia, 443

Perrieria, 319, 442

Perrinia, 408

Persicula, 425

Persona (= Distortio), 420

Petenia, 353, 440

Petersia, 420

Petraeus, 295, 331, 442

Petricola, 454

Phacellopleura, 403

Phanerophthalmus, 430

Phaneta, 408

Phania, 312, 441

Pharella, 457

Pharus, 457

Pharynx, 210

Phasianella, 409

Phasis, 333

Phenomena of distribution, 362

Philine, 245, =428=, 430; protective coloration, 73; radula, 229, 230

Philomycus, 245, 318, 440

Philonexis, =138=

Philopotamis, 304, 417

Phoenicobius, 315, 441

Pholadacea, 457

Pholadidea, 457

Pholadomya, 459

Pholas, 245, 274, 447, 457; in fresh water, 15

Phos, 424

Photinula, 408

Phragmophora, 386

Phyllidia, 434; breathing organs, 159

Phyllirrhoe, 360, 428, 433

Phyllobranchus, 432

Phylloceras, =398=, 398; suture, =396=

Phylloteuthis, 390

Physa, 439; aestivating out of water, 27; spinning threads, 29; sudden appearance, 46; osphradium, 195; nervous system, =205=; radula, =235=; P. hypnorum, 23, 27

Pileolus, 410

Pileopsis, 76

Piloceras, 394

Pinaxia, 423

Pineria, 442

Pinna, 449; shell, =254=

Pinnoctopus, 385

Pinnotheres, 62

Pinoceras, 398

Pirena, 417

Pirenella, 416

Piropsis, 424

Pirula--see Pyrula

Pisania, 424

Pisidium, 453; smell, 195; ova, 146; P. pusillum, distribution, 282

Pitys, 327

Placobranchus, 432

Placostylus, 322, =323=-325, 359, 442; radula, 233

Placuna, 448; P. placenta used for windows, 101

Placunanomia, 448

Placunopsis, 448

Plagioptycha, 347–351, 441

Plagioptychus, 456

Planaxis, 417

Planispira, 311, 312, 319, 441

Planorbis, 27, 247, 439; monstrosity, 93; eye, 181; P. albus, distribution, 282

Platyceras, 76, 412

Platydoris, 434

Platypoda, 411

Platyschisma, 413

Plaxiphora, 403

Plecochilus, 442

Plecotrema, 439

Plectambonites, 505

Plectomya, 459

Plectopylis, 303, 305, 314, 316; aperture, =63=

Plectostylus, 358, 442

Plectotropis, 305, 306, 310, 311, 314–318, 441

Plectrophorus, 298

Plesiastarte, 451

Plesiotriton, 420

Pleurobranchaea, 431; jaws, =212=

Pleurobranchoidea, 431

Pleurobranchus, 245, =428=, 431; warning coloration, 73; jaws, =212=; radula, 230

Pleurocera, 340, 417

Pleuroceridae, origin, 17

Pleurodonta, 348; aperture, =63=

Pleuroleura, 433

Pleuromya, 458

Pleurophorus, 451

Pleurophyllidia, 433; breathing organs, =159=; radula, 230

Pleuropyrgus, 357

Pleurotoma, =426=, 426; slit, =263=, 265

Pleurotomaria, =266=, 373, 376, =407=, 407; prices given for recent, 122; slit, 156; radula, 226

Plicatula, 450

Pliny the elder, on use of snails, 118, 120

Plocamopherus, 434

Plochelaea, 425

Plutonia, 298, 440

Pneumoderma, 158, 437, =438=

Poecilozonites, 352, 440

Poisonous bite of Conus, 65; poisonous oysters, 114; mussels, 117

Polycera, 434; radula, 230

Polycerella, 434

Polyconites, 456

Polydontes, 346–351, =347=, 441

Polygona, 424

Polygyra, =340=, 345–353, 441; aperture, =63=

Polygyratia, =246=, 263, 357, 442

Polymita, 346–351, =347=, 441

Polyplacophora, 9, 401 f.; radula, 228

Polytremaria, =266=, 407

Pomatia, 285, =293=, 295, 441

Pomatias, 288, 289, 292 f., 302, 413

Pomatiopsis, 415

Pomaulax, 409

Pompholyx, 250, 341, 439

Ponsonbya, 332

Poromya, 459; branchiae, 168

Porphyrobaphe, 27, 356, 442

Position of Mollusca in Animal Kingdom, 4

Potamides, =16=, 416

Potamomya, 15

Potamopyrgus, 325, 326, 415

Poterioceratidae, 394

Praecardium, 459

Prasina, 449

Prices given for rare shells, 121

Primitive mollusc, form of, 245; types of, 7

Prisogaster, 409

Pristiloma, 341, 440

Proboscidella, 497, 504

Productidae, 497, 500, 504, 508

Productus, 492, 501, =502=, 504; stratigraphical distribution, 508

Promachoteuthis, 389

Proneomenia, 404; breathing organs, 154; nervous system, =203=; radula, 229

Prophysaon, 341, 441; habits, 44

Propilidium, 405

Proserpina, =21=, 355, 410

Proserpinella, 354, 410

Proserpinidae, relationships, 21

Prosobranchiata, 9, 404 f.; breathing organs, 154

Prosocoelus, 451

Protective coloration, 69 f.; in snails, 70; in Nudibranchs, 71 f.; in other Mollusca, 74

Protegulum, 509

Protobranchiata, 447; branchiae, =166=

Protoma, 417

Protremata, 511

Provocator, 376, 425

Psammobia, 456

Pseudachatina, 328–330, 443

Pseudedmondia, 452

Pseudobalea, 350

Pseudo-deltidium, 498, 511

Pseudodon, 295, 307, 452

Pseudolamellibranchiata, 167, 449

Pseudoliva, 424

Pseudomelania, 417

Pseudomilax, 296, 440

Pseudomurex, 423

Pseudopartula, 323

Pseudosubulina, 440

Ptenoglossa, 224, 411

Pterinaea, 449

Pteroceras, 256, 262, 418

Pteroctopus, 384

Pterocyclus, =266=, 267, 300, 316, 414; tube, 157

Pterodonta, 418

Pteropoda, 7, 434; breathing organs, 158; foot, 200; radula, 230

Pterotrachaea, 421; foot, 200; radula, =227=

Ptychatractus, 424

Ptychoceras, 399

Ptychodesma, 452

Pugilina, 424

Pulmonata, 10, 22, 151, 185, 438; origin, 17, 19; breathing organs, 160; nervous system, 203

Pulsellum, 444

Punctum, 441

Puncturella, =265=, 406

Pupa, 289, 296, 325–357, 442; P. cinerea, hybrid union, 129

Pupidae, radula, 233

Pupilla, 442

Pupillaea, 406

Pupina, 157, 266, 309, 318–327, 414

Pupinella, 318, 414

Purpura, 423; operculum, =269=; erosion, 276; P. coronata, 367; lapillus, feeding on Mytilus, 60; on oysters, 111; protective coloration, 69; variation, =90=; egg-capsules, 124; time of breeding, 129; distribution, 363 n.

Purpuroidea, 423

Pusionella, 426

Pygocardia, 451

Pygope, 497

Pyramidella, 422

Pyramidellidae, 262

Pyrazus, 50, 416

Pyrgina, 330

Pyrgula, 415

Pyrochilus, 441

Pyrolofusus, 423

Pyrula (= Pirula), 419, =420=; spawn, =125=; operculum, =269=

Pythina, 453

Quenstedtia, 456

Quoyia, 260, 417

Rachiglossa, 220, 422; eggs, 124

Rachis, 329–335, 441, 442

Radiolites, 456

Radius, 419

Radsia, =403=

Radula, 213 f.; of Littorina, =20=; of Cyclophorus, =21=; of parasitic Mollusca, 79

Raëta, 454

Ranella, 256, 420

Range of distribution, 362 f.

Rangia, 15, 453

Ranularia, 420

Rapa, 423

Rapana, 423

Raphaulus, 305, 309

Rathouisia, 316, 440

Rats devouring Mollusca, 57

Realia, 316, 327, 414

Recluzia, 411

Rectum, 241

Registoma, 414

Relationship of Mollusca to other groups, 5

Renssoellaria, 512

Reproductive activity of oyster, 112; system in Mollusca, 123, 134 f.

Requienia, 269, =455=, 455

Respiration, 150 f.

Retzia, 508

Revoilia, 331, 414

Reymondia, 332

Rhabdoceras, 398

Rhagada, 311, 324

Rhenea, 325, 440

Rhinobolus, 504

Rhiostoma, 247, =266=, 309, 414

Rhipidoglossa, 225, 405

Rhizochilus, 75, 423

Rhodea, 356, 441

Rhodina, 307, 310, 442

Rhynchonella, 466, 470, 471, 472, 474, 483, 487; distribution, 487; fossil, 492, 497, 499, 505; stratigraphical distribution, 506, 507, 508, 511

Rhynchonellidae, 487, 501, 505; stratigraphical distribution, 507, 508, 511

Rhysota, 67, 310, 314, 316, 319, 440

Rhytida, 319–326, 333, 359, 440; habits, 54; radula, =232=

Rillya, 442

Rimella, 418

Rimula, 265, 406

Ringicula, 430; radula, 230

Risella, 413

Rissoa, 415

Rissoina, 415

Robillardia, 77

Rochebrunia, 331, 414

Rock-boring snails, 49

Rolleia, 349

Rossia, 389

Rostellaria, 418

Rudistae, 456

Rumina, 260, 442

Runcina, 431; protective coloration, 73

Sabatia, 430

Sactoceras, 394

Sagda, =348=-351, 441

Sageceras, 398

Salasiella, 353, 440

Salivary glands, 237

Sandford, on strength of Helix, 45

Sandwich islanders, use of shells, 99

Sanguinolaria, 456

Sarepta, 447

Sarmaticus, 409

Satsuma, 314, 316, 441

Saxicava, 447, 457

Saxidomus arata, money made from, 97

Scalaria, 247, 263, 411; radula, 224

Scaldia, 452

Scalenostoma, 422

Scaliola, 415

Scaphander, =428=, 429, 430; radula, =231=; gizzard, =238=

Scaphites, =399=, 399

Scaphopoda, 444; defined, 6; breathing organs, 160; nervous system, 205; radula, 236

Scaphula, =14=, 305, 448

Scarabus, =18=, 278, =439=, 439

Scharff, R., on food of slugs, 31; on protective coloration in slugs, 70

Schasicheila, 347, 351, 354, 410

Schismope, =266=, 407

Schizochiton, 187, 402, 403

Schizodus, 448

Schizoglossa, 325, 440

Schizoplax, 403

Schizostoma, 413

Schloenbacia, 398

Scintilla, 175, 453

Scissurella, 265, 407; radula, 226

Sclerochiton, 403

Scrobicularia, 15, =164=, 453; siphons, =164=

Sculptaria, 333

Scurria, 405

Scutalus, 356, 442

Scutellastra, 405

Scutus, 245, =406=, 406

Scyllaea, 433; jaws, =212=; stomach, 239

Segmentina, 320

Selenites, 339, 341, 440

Selenitidae, radula, 231

Selenochlamys, 296

Self-fertilisation, 42–44

Semele, 453

Semicassis, 420

Semper, K., on habits of Limnaea, 34; of Helicarion, 45, 67; on mimicry, 67; on parasitic Eulima, 79; on development of Limnaea, 84, 94; on sexual maturity in snails, 129; on Onchidium, 187

Sepia, 381, 385–=387=, 389; egg-capsules, =127=; glands, 136; jaws, =214=; radula, 236; alimentary canal, =238=; ink-sac, =241=; hectocotylus, =389=

Sepiadarium, 389

Sepiella, 389

Sepiola, 389; glands, 136; radula, 236

Sepioloidea, 389

Sepiophora, 388

Sepioteuthis, 390; hectocotylus, 139

Septaria, 337, 338, 410

Septibranchiata, 145, 167, 459; branchiae, =166=

Septifer, 274, 449

Sequenzia, 420

Sergius Orata, 104

Serrifusus, 424

Sesara, 305, 440

Sex, differences of, 133

Shell, 244 f.; internal, 174; shape of bivalve, 445

Shell-gland, primitive, 132

Shells as money, 96 f.; as ornament, etc., 98 f.; various uses of, 98 f.; prices given for rare, 121; sinistral, 249

Shores of N. Asia, no littoral fauna, 2

Showers of shells, 47

Sigaretus, =186=, =245=, 267, 411; foot, =198=

Sight, 180

Silenia, 459; branchiae, 168

Silia, 425

Siliqua, 274, 457

Siliquaria, =248=, 418

Simnia, 419

Simpulopsis, 345, 350, 442

Simpulum, 420

Simroth, on recent forms of Helix, 22; on food of slugs, 31; on crawling of Helix, 45

Singular habitat, 48

Sinistral shells, 249

Sinistralia, 424

Sinusigera, 133

Sipho, 424

Siphonalia, 424

Siphonaria, 18, 431; classification, 19; breathing organs, 151, =152=

Siphonarioidea, 431

Siphonodentalium, 444

Siphonostomata, 156

Siphonotreta, 493, 496, 504; stratigraphical distribution, 507, 508

Siphons, 173; in burrowing genera, 165; branchial, 155

Sistrum, 75, 423; radula of S. spectrum, 79, =222=

Sitala, 301, 304, 310, 314–319, 333, 440

Skärgard, Mollusca of the, 13

Skenea, 415

Skenidium, 505, 508

Slit, in Gasteropoda, 265, 406

Slugs, habits and food of, 30 f.; bite hand of captor, 33; in bee-hives, 36; in greenhouses, 36; protective coloration, 70; eaten in England, 120

Smaragdia, 21

Smaragdinella, 430

Smell, sense of, 192

Smith, W. Anderson, quoted, 98, 111, 114, 191

Snails as barometers, 50; plants fertilised by, 102; cultivation for food, 118 f.; used for cream, 119; as medicine, 120; banned by the Church, 121

Solariella, 408; radula, 225

Solarium, =264=, 412, =413=; radula, 224

Solaropsis, 343, 353–357, 442

Solecurtus, =165=, 457

Solen, 171, 446, 457; vision, 190; habits, 45

Solenaia, 452

Solenomya, 275, 448

Solenotellina, 456

Solomon islanders, use of shells, 98

Somatogyrus, 415

Sophina, 305

Spallanzani, experiments on Helix, 163

Spat, fall of, 113

Spatha, 294, 331, 336, 452

Spekia, =333=

Spermatophore, in Cephalopoda, 137; in Helix, 142

Spermatozoa, forms of, 136

Sphaerium, 453

Sphenia, 456

Sphenodiscus, 398

Sphyradium, 442

Spines, use of, 64

Spiraculum, 266, 414

Spiraxis, 442

Spirialis, 249

Spirifera, 468, =501=, 505; stratigraphical distribution, 507, 508, 511, 512

Spiriferidae, 501, 505, 508

Spiriferina, stratigraphical distribution, 507, 508

Spirobranchiata, 464

Spirotropis, 426; radula, 218, =219=

Spirula, 247, 386, 387, =388=

Spirulirostra, 380, 386, 388

Spondylium, 500

Spondylus, 257, 446, =450=, 450; ocelli, 191; genital orifice, 242

Spongiobranchaea, 437

Spongiochiton, 403

Sportella, 453

Starfish eat oysters, 110

Stearns, R. E. C., on tenacity of life, 38

Stegodera, 306

Stenochisma, 505; stratigraphical distribution, 507, 508

Stenogyra, 324, 442; S. decollata, 279; food, 34; smell, 194; Goodallii, 279; octona, sudden appearance, 47

Stenogyridae, radula, 234

Stenopus, 440; habits, 45

Stenothyra, 415

Stenotis, 416

Stenotrema, 340, 441

Stephanoceras, 399

Stepsanoda, 358

Stilifer, 76, 77, 79, 422

Stiliferina, 76, 422

Stiliger, 432

Stilina, 76

Stoastoma, 348–351, 410

Stoloteuthis, 389

Stomach, 239

Stomatella, 408

Stomatia, 408

Stomatodon, 302, 417

Strebelia, 353, 440

Strength of Helix, 45

Strephobasis, 417

Strepsidura, 424

Streptaulus, 414

Streptaxis, =302=, 306, 309, 314–331, 343, 357–359, 440; variation, 87

Streptoneura, 203, 404

Streptosiphon, 424

Streptostele, 329, 338, 440

Streptostyla, 343–355, =353=, 440

Stricklandia, 505; stratigraphical distribution, 507, 508

Strigatella, 425

Stringocephalidae, 506, 508

Stringocephalus, 492, 497, =498=, 500, 501, 506; stratigraphical distribution, 507, 508

Strobila, 340, 345–353

Strobilops, 442

Strombidae, habits, 64; penis, 136

Strombina, 423

Strombus, =69=, =200=, 252, 418; mimicking Conus, 69; operculum, =78=, =269=; pearls from, 101; metapodium, 199; stomach, 239

Strophalosia, 504; stratigraphical distribution, 507, 508

Stropheodonta, 497, 505, 508

Strophia, 343–355, 442; S. nana, 278

Strophochilus, 358, 441

Strophomena, 499, 505; stratigraphical distribution, 507, 508

Strophomenidae, 500, 505, 508

Strophostoma, 248, 414

Structure of shell, 252

Struthiolaria, 99, 418; radula, 216

Styliola, 437

Stylodonta, 339, 441

Stylommatophora, 11, 181, 439; origin, 19

Subemarginula, 406

Submytilacea, 451

Subularia, 422

Subulina, 332, 352, 442

Subulites, 420

Succinea, 325, 327, 358, 433; jaw, =211=; S. putris, parasite of, 61

Succineidae, 443; radula, 234

Sudden appearance of Mollusca, 46

Suessia, stratigraphical distribution, 507

Sulphuric acid, 237

Surcula, 426

Sycotypus, 424

Synaptocochlea, 408

Syndosmya, 453

Syringothyris, 500, 508

Syrnola, 422

Syrnolopis, 332, =333=

Systrophia, 356, 357

Tachea, 441

Taenioglossa, 223, 411

Taheitia, 414

Talona, 457

Tanalia, 304, 417

Tancredia, 453

Tanganyicia, 332, 415

Tanganyika, L., fauna of, 12

Tanysiphon, 454

Taonius, =391=, 391

Tapes, 454

Taste, 179

Tebennophorus, 143, 340, 440

Tectarius, 413

Tectibranchiata, 10, 429

Tectura, 305, 405

Tectus, 408

Teeth in aperture of the shell, 63

Teinostoma, 247, 408

Teinotis, 407

Telescopium, 252, 416

Tellina, 440, =453=, 453; T. balthica, variation, 84

Tellinacea, 453

Telotremata, 511

Tenacity of life, 37

Tenison-Woods, on red blood, 171; on shell-eyes, 189

Tennent, Sir J. E., on musical sounds produced by Mollusca, 50

Tennentia, 304, 314, 338, 440

Terebellum, 418; jumping powers, 64

Terebra, =246=, 263, =426=, 426; radula, =219=

Terebratella, 468, 487; distribution, 486; fossil, 506; stratigraphical distribution, 508

Terebratula, 467, 468, 487; size, 484; distribution, 485, 486; fossil, 492, =499=, 506; stratigraphical distribution, 506, 507, 508

Terebratulidae, 487; fossil, 500, 505, 506; stratigraphical distribution, 507, 508

Terebratulina, =466=, 479, 487; larva, =482=; distribution, 486; fossil, 506; stratigraphical distribution, 508; form of shell, 510

Teredina, 457

Teredo, 262, =457=, 458; nervous system, =206=; intestine, =241=

Tergipes, 432

Terquemia, 450

Testacella, 22, =52=, 440; habits, etc., 49, 51 f.; pulmonary orifice, 160; eyes, 186; radula, 231; anus, 241

Testicardines, 466, 487; muscles, 476; fossil, 497, 504; external characters, 497; internal characters, 499; attachment of muscles, 501; stratigraphical distribution, 508

Testis, 135

Tethyidae, 216

Tethys, 432

Tetrabranchiata, 391 f.

Thala, 425

Thalassia, 319

Thalotia, 408

Thapsia, 329

Thaumasia, 349, 442

Thaumastus, 356, 442

Thecacera, 434; radula, 229

Thecidiidae, 487; fossil, 501, 506, 508

Thecidium, 475, 479, =480=, 483, 487; fossil, 506, 508

Thecosomata, 435

Thelidomus, 346–351, =350=, 441

Theora, 453

Therasia, 441

Thersites (Helicidae), 322, 325

Thersites (Fasciolariidae), 424

Thetis, 454

Thracia, 245, 459

Thread-spinning, 29

Thridachia, 432

Thyca, 76, 79

Thyrophorella, 330, 440

Thysanoteuthis, 390

Tiedemannia, veliger, =132=

Tiphobia, 332, =333=, 417

Titicaca, L., Mollusca of, 25

Todarodes, 390

Tomichia, 414

Tomigerus, 334, 356, 358, 442

Tomocyclus, 354

Tomostele, 330, 440

Tonicella, 403

Tonicia, 403; eyes, 188

Torellia, 411

Torinia, 413; radula, 224; operculum, =269=

Tornatellina, 278, 319, 323–327, 338, 358, 443

Tornatina, 250, 430

Torquilla, 442

Toucasia, 455

Touch, sense of, 177

Toxoglossa, 218, 426

Trachia, 314

Trachyceras, 397

Trachydermon, 403

Trachyteuthis, 389

Tralia, 439

Transovula, 419

Trematis, 492, 493, 504; stratigraphical distribution, 507, 508

Trematonotus, 407

Tremoctopus, 384; radula, 236; hectocotylus, 137

Trevelyana, 434

Trichia, 316

Trichotropis, 275, 411

Tricula, 302

Tridacna, =273=, 455

Triforis, 416; radula, 224

Trigonellites, =397=

Trigonia, =15=, 254, 269, 448; jumping powers, 65; distribution, 370

Trigonochlamys, 296, 440

Trigonostoma, 426

Trimerella, =495=, 504, 508, 511

Trimerellidae, 493, 494, 496, 504; stratigraphical distribution, 507, 508

Trinacria, 448

Triodopsis, 340, 441

Triopa, 434

Triopella, 434

Triopha, 434

Tritaxeopus, 385

Triton, 256, =275=, 420; jaws, =212=

Tritonia, 433; protective coloration, 71

Tritonidea, 424

Trivia, 419

Trochidae, egg-capsules, 125

Trochiscus, 408

Trochita, 248, 412

Trochoceras, 395

Trocholites, 395

Trochomorpha, 306, 321, 324, 327, 333, 441

Trochonanina, 331, 440

Trochosphere, 5, 130

Trochotoma, 266, 407

Trochus, 263, 408; eye, 182; stomach, 239

Trophon, 423

Tropical beach, Mollusca of a, 3

Tropidophora, 414

Tropites, 397

Troschelia, 424

Truncaria, 423

Truncatella, 260, 414

Tryblidium, 405

Trypanostoma, 340

Trypho of Lampsacus, prayer against snails, 121

Tubed operculates, 157, 266, 300, 307, 309

Tudicla, 424

Tudora, 291, 349, 351, 414

Tugonia, 456

Tulotoma, 340, 416

Turbinella, 100, 262, =264=, =424=, 424

Turbo, 409; eye, =182=; osphradium, 195; operculum, =268=

Turbonilla, 250, 332, 422

Turcica, 408

Turricula, 425; radula, 221

Turrilites, =399=, 399

Turritella, 252, 417; radula, 215, 224

Tyleria, 459

Tylodina, 431

Tylopoma, 416

Tympanotonus, 416

Tyndaria, 447

Typhis, 423

Ultra-dextral shells, 250

Umbonella, 409

Umbonium, 409

Umbrella, =10=, 431; radula, 217, 230

Uncites, 505; stratigraphical distribution, 507, 508

Underground snails, 48

Ungulina, 452

Unicardium, 452

Unio, 452; shell, =254=, 259, =273=, 341; variation, 92

Union of Limax, 128

Unionidae, origin of, 15; eaten by rats, 57; larvae, 146

Urocyclus, =331=, 440

Urosalpinx, 423

Utriculus, 430

Uvanilla, 409

Vaginula, 245, 319, 343, 352, 443

Vaginulidae, radula, 234; anus, 241

Valletia, 456

Vallonia, 441

Valvata, 133, 416; branchia, =159=

Valves of Chitonidae, 401 f.

Vanganella, 454

Variation, 82 f.

Varicella, 346, 348

Velates, 260, 410

Velifera, 353, 440

Veliger stage, 131; mistaken for perfect form, 133

Velorita, 302, 453

Velum, 131

Velutina, 275, 411; radula, 223

Veneracea, 454

Venericardia, 451

Venerupis, 454

Veniella, 451

Venilicardia, 451

Venus, =270=, =271=, 446, 454; V. mercenaria, 97, 374

Verania, 391

Vermetus, 247, 418; radula, =223=

Veronicella, 443

Verticordia, 458

Vertigo, 327, 442; V. arctica, 287

Vexilla, 423

Vibex, 417

Vitrella, 289

Vitrina, 22, 296 f., 332, 440; hardy habits, 24; jumping powers, 65; shell, 175; radula, 217

Vitrinella, 408

Vitriniconus, 314, 440

Vitrinoidea, 314, 440

Vitrinozonites, 340, 440

Vitularia, 423

Vivipara, 324, 343, 416

Volume of water, effect in producing variation, 94

Voluta, 267, =425=, 425; spawn, =125=; radula, 217, 221; distribution, 370; prices given for rare, 122

Volutaxis, 348

Volutharpa, 267, 424

Volutolithes, 425

Volutolyria, 425; radula, 222

Volutomitra, 425; radula, 221

Volutopsis, 423

Volvaria, 429

Volvatella, 430

Volvula, 430

Vulsella, 75, =446=, 449

Waldheimia, 464, 467, 468, 473, 474, 487; size, 484; distribution, 486; fossil, =500=, 501, 502, 506, 508

Walton and mussel cultivation, 115

Wampum, 97

Warner, R., quoted, 37

Warning coloration, 71 f.

West Coast, South America, melanism of shells occurring on, 85

Whelks, use of, 118

Whitneya, 424

Whitstable, oyster-parks at, 106, 112

Willem, V., on vision of Mollusca, 185

Wollaston, T. V., quoted, 32

Wood, Rev. J. G., on starfish eating oysters, 111

Woodia, 451

Woodward, S. P., on tenacity of life, 38; Dr., on the same, 38

Wotton, F. W., on egg-laying of Arion, 42

Wright, Bryce, on tenacity of life, 38

Xenophora, 412; habits, =64=

Xenopoma, 346, 351

Xerophila, 285, 296, 441

Xesta, 310, 319, 321, 440; mimicry by, 66 f.

Xylophaga, 457

Yetus, 425

Yoldia, 447; genital orifice, 242

Zagrabica, 297

Zebrina, 285, 296, 442

Zeidora, 406

Zidona, 425

Zittelia, 420

Zones of depth, 361

Zonites, 275, 440; food, 33; radula, 232; distribution, 294, 296, 340

Zospeum, 187, 442

Zygobranchiata, 154, 406

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FOOTNOTES:

See especially Moseley, Nature, 1885, p. 417.

Quart. Journ. Conch. i. p. 371.

Manuel de Conchyliologie et de Paléontologie Conchyliologique. Dr. P. Fischer. Paris, 1887.

κεφαλή, head; γαστήρ, stomach; σκάπτειν, to dig; πέλεκυς, an axe; πούς, ποδός, a foot.

Also known as Lamellibranchiata, Conchifera, and Acephala.

πτερόν, wing.

γλῶσσα, tongue; φέρειν, to carry.

λείπειν, to be wanting.

ἀμφί, on both sides; νεὕρον, nerve, vessel. Some authorities regard the Amphineura as a distinct Order.

πολύς, many; πλάξ, plate.

πρόσω, in front. Often alluded to in the sequel as ‘operculate Gasteropoda.’

κτενίδιον, a little comb.

δὐω, two; mόnos, single; ὦτα, auricles; καρδία, heart.

ὄπισθεν, behind.

Pulmo, a lung.

στὕλος, pillar; ὄμματα, eyes.

The Ascoglossa are dealt with below (chap. xv.).

Beudant, by very gradually changing the water, accustomed marine species to live in fresh, and fresh-water species to live in salt water.

Braun, Arch. f. Naturk. Liv. (2), x. p. 102 f.

Lindström, Oef. K. Vet. Förh. Stockh., 1855, p. 49.

Mendthal, Schr. Ges. Königsb., xxx. p. 27.

SB. K. Akad. Wiss. Wien, 1889, p. 4, but the view is not universally accepted.

Not to Nassa, as has been generally held. The shape of the operculum, and particularly the teeth of the radula, show a much closer connexion with Cominella.

E.g. Bouvier, Le Natural, 1889, p. 242.

Köhler, Zool. Jahrb. vii. 1893, p. 1 f; Haller, Arb. Zool. Inst. Wien, x. p. 71.

Plate, SB. kön. Preuss. Ak. Wiss. Berl. 1893. p. 959.

E.g. Pelseneer, Bull. Sc. France Belg. xxiv. p. 347 f.

E.g. Bergh, Zool. Jahrb. v. p. 1 f.

Calkins, Amer. Nat. xi. p. 687.

One step even further (or perhaps it should be termed a branch derivative) is seen in the genus Smaragdia, which is probably a Neritina which has resumed a purely marine habit of life.

SB. Naturf. Gesell. Leipz. 1886–87, pp. 40–48.

L. and F. W. Moll. of India, iv. p. 167.

T. Scott, Journ. of Conch. v. p. 230.

J. S. Gibbons, ibid. ii. p. 129.

Bull. Soc. Linn. Nord, Abbeville, 1840, p. 150.

Joly, Comptes Rendus, 1842, p. 460; compare W. A. Gain, Science Gossip, xxvii. p. 118.

Von Martens, SB. Nat. Fr. Berl. 1881, p. 34.

Moquin-Tandon, Moll. de France, i. p. 116.

Journ. of Conch. iii. p. 321 f.; iv. p. 13; Science Goss. 1866, p. 158.

Reichel, Zool. Anz. x. p. 488.

Schumann, Schr. Ges. Danz. (2) vi. p. 159.

Fischer and Crosse, Mexico, p. 437.

Journ. de Conch. iv. p. 397, but the species observed is not mentioned.

Bull. Mus. C. Z. Harv. iv. p. 378.

W. Harte, Proc. Dubl. N. H. Soc. iv. p. 182.

See on the whole subject of threads G. S. Tye, Journ. of Conch. i. p. 401.

Zoologist, ii. p. 296; iii. p. 833; iv. p. 1216; iii. p. 1036; iv. p. 1216; iii. p. 1037.

Ann. Nat. Hist. ii. 1838, p. 310.

H. W. Kew, Naturalist, 1889, p. 103.

Zeit. wiss. Zool. xlii. p. 203 f.

Sci. Trans. R. Dubl. Soc. (2) iv. p. 520.

Zoologist, iv. p. 1504; iii. p. 1038; iii. p. 943.

H. W. Kew, l. c.

Zoologist, xix. p. 7819.

Naturalist, 1889, p. 55.

H. W. Kew, l. c.

W. G. Binney, Bull. Mus. C. Z. Harv. iv. p. 144.

Naturalist, l. c.

Science Gossip, 1885, p. 154.

R. Standen, Journ. of Conch. vii. p. 197.

Journ. of Conch. v. p. 43.

A. Paladilhe in MS. letter.

J. S. Gibbons, Quart. Journ. Conch. ii. p. 143.

Bull. Mus. C. Z. Harv. iv. p. 193.

l. c. p. 362.

Animal Life, p. 59.

Zoologist, 1861, p. 7400; Brit. Conch. i. p. 108.

H. Ullyett, Science Gossip, xxii. (1886), p. 214.

Descent of Man, i. p. 325, ed. 1.

Amer. Nat. xv. 1881, p. 976.

W. A. Gain, quoted by H. W. Kew in Naturalist, 1890, p. 307, an article to which I am much indebted.

Ann. Mag. Nat. Hist. (5) xvi. p. 519.

Science Gossip, 1882, pp. 237, 262.

H. W. Kew, Naturalist, 1893, p. 149, another most valuable article.

Garden, v. p. 201, quoted by Kew, ut sup.

Kew, ut sup.

Science Gossip, 1883, p. 163.

T. D. A. Cockerell, Science Gossip, 1885, p. 211.

Ann. Mag. Nat. Hist. (2) vi. (1850) p. 68.

Ann. Mag. Nat. Hist. (2) vi. p. 489.

Ibid. (3) iii. p. 448.

Amer. Nat. xi. (1877) p. 100; Proc. Calif. Ac. iii. p. 329.

Gaz. Med. Alger. 1865, 5th Jan. p. 9.

Science Gossip, 1867, p. 40.

Ann. Mag. Nat. Hist. (2) ix. p. 498.

Journ. of Conch. vi. p. 101.

Naturalist, 1889, p. 55.

Malak. Blätt. (2) iv. pp. 43 and 221.

Phil. Trans. 1854 (1856), p. 8.

Naturalist, 1891, p. 75 f.; Conchologist, ii. 1892, p. 29.

Taylor, Journ. of Conch. 1888, p. 299.

See Tennent’s Ceylon, i. p. 221, ed. 5.

W. A. Gain, Naturalist, 1889, p. 55; Brockmeier, Nachr. Deutsch. Malak. Gesell. xx. p. 113.

Ann. Mag. Nat. Hist. (2) ix. p. 498.

Journ. Conch. vii. 1893, p. 158 f.

I succeeded in hatching out eggs of Helix aspersa, during the very warm summer of 1893, in 17 days.

Nachr. Deutsch. Malak. Gesell. xx. p. 146.

Raymond, Nautilus, iv. p. 6.

Quoted by Oehlert, Rév. Sc. xxxviii. p. 701.

Animal Life, Intern. Scientif. Ser. ed. 1, p. 395.

Zoologist, 1886, p. 491.

Thomas, quoted by Jeffreys, Brit. Conch. i. p. 30.

Journ. of Conch. iv. p. 117.

Rev. L. Jenyns, Observations in Nat. Hist. p. 318.

Id. ib. p. 319.

Further detailed examples will be found in Kew, The dispersal of Shells, pp. 5–26.

P. Z. S. 1888, p. 358.

W. A. Gain, Naturalist, 1889, p. 58.

Das Wetter, Dec. 1892. Another case is recorded in Amer. Nat. iii. p. 556.

Zoologist, x. p. 3430.

Science Gossip, 1888, p. 281.

Lecoq, Journ. de Conch. ii. p. 146.

Bouchard-Chantereaux, Ann. Sci. Nat. Zool. (4) xvi. (1861) p. 197.

Forel, Ann. Sci. Nat. (3) xx. p. 576; Bretonnière, Comptes Rendus, cvii. p. 566.

Brit. Mus. Collection.

Thomas, quoted by Récluz in Journ. de Conch. vii. 1858, p. 178.

Nat. Hist. of Ceylon, p. 382. See also T. L. Taylor, Rep. Brit. Ass. for 1848, p. 82.

Dr. R. E. Grant, Edinb. Phil. Journ. xiv. p. 188.

Rep. Brit. Ass. for 1848, p. 80. The statement is confirmed by Rossmässler.

Journ. of Conch. iv. p. 118.

Zoologist, 1887, p. 29.

Arch. Zool. Exp. Gén. (2) v. p. 459 f.

Journ. of Conch. iii. p. 277; compare W. M. Webb, Zoologist, 1893, p. 281.

Bull. Mus. Comp. Zool. Harv. iv. p. 85.

Erjavec, Nachr. Deutsch. Malak. Gesell. 1885, p. 88.

Crosse, Journ. de Conch. (3) xiv. (1874) p. 223.

C. Wright, Zoologist, 1869, p. 1700.

W. V. Legge, Zoologist, 1866, p. 190.

Blackwall, Researches, p. 139.

Barrow, Travels in South Africa, ii. p. 67.

Loch Creran, p. 102.

Cordeaux, Zoologist, 1873, p. 3396.

Amer. Nat. xii. p. 695; Science Gossip, 1865, p. 79.

Journ. Trent. N. H. Soc. 1887, p. 58.

Ann. Nat. Hist. iii. 1893, pp. 238, 239.

Rev. Nat. Sc. Ouest, 1891, p. 261.

Petit de la Saussaye, Journ. de Conch. iii. p. 97 f.

J. W. Williams, Science Gossip, 1889, p. 280.

Noack, Zool. JB. ii. p. 254.

La Nature, xv. (2) p. 46.

François, Arch. Zool. Exp. Gén. (2) ix. p. 240.

A. Lang, Ber. Naturf. Ges. Freib. vi. 1892, p. 81.

A. P. Thomas, Q. J. Micr. Sc. N. S. xxiii. (1883) p. 99.

H. Woodward, P. Z. S. 1886, p. 176.

W. E. Collinge, Zoologist, 1890, p. 467.

Proc. Linn. Soc. N. S. Wales, ix. p. 944.

Zoologist, xviii. (1860) p. 7136.

A. Adams, Samarang, vol. ii. Zoology, p. 357.

In Thomson’s British New Guinea, p. 283.

Animal Life, p. 395. It should be mentioned that Von Möllendorff (Ber. Senck. Ges. 1890, p. 198) ridicules the whole theory.

Von Martens, SB. Nat. Fr. Berl. 1891, p. 83.

Von Martens, ibid. 1887, p. 183.

SB. Nat. Gesell. Leipz. xiii.-xiv. p. 45.

Garstang, Journ. Mar. Biol. Ass. N. S. i. p. 432; Giard, Bull. Sci. Fr. Belg. 1888, p. 502 f.

Nautilus, vi. 1892, p. 90.

R. F. Scharff, Sci. Trans. R. Dubl. Soc. (2) iv. p. 553 f.

Q. Journ. Micr. Sci. N. S. xxxi. (1890) p. 41 f.

A detailed account is given in Proc. Liverp. Biol. Soc. iv. (1890) pp. 150–163.

Journ. Mar. Biol. Ass. N. S. i. p. 418 f.

Garstang, Conchologist, ii. p. 49.

Hecht, Comptes Rendus, cxv. p. 746.

Conchologist, ii. p. 130.

Described as a Cypraea, but no doubt an Ovula or Pedicularia: CB. Bakt. Par. v. p. 543.

Von Graff, Z. wiss. Zool xxv. p. 124.

Proc. Amer. Phil. Soc. xxv. p. 231.

Ergeb. naturw. Forsch. Ceylon, abstr. in Journ. Roy. Micr. Soc. (2) vi. p. 412.

Voyage of the Samarang, Moll. p. 69, Pl. xi. f. 1; p. 47, Pl. xvii. f. 5.

E. A. Smith, Ann. Mag. Nat. Hist. (6) iii. p. 270.

Journ. de Conch. (3) xxix. p. 101.

Zool. Jahrb. Abth. f. Syst. v. p. 619.

See especially Semper, Animal Life, Ed. 1, p. 351.

Gould, Moll. of U.S. expl. exped. 1852, p. 207 (St. acicula, from Fiji).

Stimpson, Proc. Bost. Soc. N. H. vi. 1858, p. 308.

Pidgeon, Nature, xxxix. p. 127.

W. Anderson Smith, Loch Creran, p. 46.

Smart, Journal of Conch. v. p. 152.

Animal Life, p. 351.

Journ. of Conch. vi. 1891, p. 399.

Ann. Mag. N. H. (6) vii. p. 276.

Stimpson, quoted by Jeffrey’s Brit. Conch. ii. 194.

Stimpson, Journ. Bost. Soc. N. H. vi. 1857, p. 48.

E. H. Matthews, Conchologist, ii. p. 144.

Thus Limnaea involuta, which is almost universally regarded as a good and distinct species, has been held to be no more than a variety of L. peregra produced by locality; see Zoologist, 1889, p. 154.

J. W. Taylor, Journ. of Conch. v. p. 289, an interesting article, with many useful references.

Möbius, Report on ‘Pommerania’ Exped. pp. 138–141.

Journ. de Conchyl. xxiii. 1875, p. 105.

J. W. Taylor ut sup. p. 300.

Sci. Trans. R. Dubl. Soc. (2) iv. p. 555.

J. S. Gibbons, Journ. of Conch. ii. p. 129.

C. H. Morris, ibid. vii. p. 191.

F. M. Hele, ibid. iv. p. 93.

T. D. A. Cockerell, Science Gossip, 1887, p. 67.

J. G. Jeffreys, British Conchology, vol. i. p. 214.

Journ. of Conch. vi. p. 123.

Phil. Trans. 1889, vol. 180 B, p. 207. A somewhat similar case (the celebrated Steinheim series of Planorbis) is dealt with by Hilgendorf, MB. Akad. Berl. 1866, p. 474; and Hyatt, Proc. Amer. Ass. Sc. xxix. p. 527.

J. B. Bridgman, Quart. Journ. Conch. i. p. 70.

W. C. Hey, Journ. of Conch. iii. p. 268.

Zool. Anz. xiii. p. 662.

J. Madison, Journ. of Conch. v. p. 260.

Quart. Journ. Conch. i. 339.

Whitfield, Bull. Amer. Mus. N. H. i. p. 29.

Amer. Nat. xiv. p. 51.

Animal Life, Ed. 1, p. 160 f.

Conch. Syst. ii. p. 262 n.

P. L. Simmonds, Commercial Products of the Sea, p. 278.

Benderloch, p. 118.

C. Hedley in J. P. Thomson, Brit. New Guinea, p. 283.

Most of the above facts are derived from a study of a collection of native implements, weapons, ornaments, etc., in the Antiquarian Museum at Cambridge.

Thurston, Notes on the Pearl and Chank Fisheries, Madras, 1890.

See in particular, P. L. Simmonds, The Commercial Products of the Sea.

H. Friend, Field Club, iv. 1893, p. 100.

Nature, xxxi. 1885, p. 492.

W. Anderson Smith, Benderloch, p. 173.

Dominique, Feuill. Nat. xviii. p. 22.

SB. Nat. Fr. Berl. 1889, p. 197.

A. Adams, Voyage of the ‘Samarang,’ ii. p. 308.

Much information has been derived, on this subject, from Bertram’s Harvest of the Sea, Simmonds’ Commercial Products of the Sea, the publications of the Fisheries Exhibition, especially vol. xi. (Anson and Willett); see also Philpots, Oysters and all about them.

Juvenal, Sat. iv. 140–142.

Hist. Nat. ix. 79.

Vol. Max. ix. 1.

Quart. Journ. Micr. Sc. xxvi. p. 71.

See G. H. Lewes, Sea-side Studies, p. 339.

Bull. U.S. Fish. Comm. v. p. 161.

W. Anderson Smith, Loch Creran, p. 228.

Longmans’ Magazine, June 1889.

St. James’s Gazette, 6th January 1893.

Also at Arcachon (W. A. Herdman, Nature, 1893, p. 269).

See especially Hoek, Tijdschr. Ned. Dierk. Vereen, Suppl. Deel, i. 1883.

Benderloch, p. 136.

This is the view of E. Ray Lankester, Quart. Journ. Micr. Sc. xxvi. 80.

De Quatrefages, Rambles of a Naturalist.

Quoted by Jeffreys, Brit. Conch., ii. p. 109.

M. S. Lovell, Edible Mollusks, p. 49.

Science, vii. p. 175.

Hist. Nat. ix. 82.

De re rustica, iii. 14.

Epistles, i. 15.

Hor. Sat. II., iv. 58, tr. Conington.

Roberts, Zoologist, 1885, p. 425.

Hist. Nat. xxx. 15, 19.

Science Gossip, 1891, p. 166.

Jeffreys, Brit. Conch. iii. p. 355.

W. Clark, Mag. Nat. Hist. xvi. p. 466.

Examples will be found in Journ. Linn. Soc. Zool. xi. p. 90; Ann. Sc. Nat. xx. p. 472; Zeit. wiss. Zool. xxiv. p. 419.

Herdman, Proc. Liverp. Biol. Soc. iii. p. 30.

Garrett, Journ. Ac. Nat. Sc. Phil. viii. (1880).

J. Bladon, Zoologist, xvi. p. 6272.

Lo Bianco, MT. Zool. Stat. Neap. viii. p. 414.

Animal Life, pp. 126, 135.

R. Rimmer, Land and Fresh-Water Shells, p. 119.

Journ. de Conch. ii. p. 245.

Journ. de Conchyl. iii. p. 107.

Jeffreys, Brit. Conch. iii. p. 359; Sauvage, Journ. de Conchyl. xxi. p. 122.

Hermaphroditism seems to occur in (a) whole families, e.g. Anatinidae and the Septibranchia; (b) genera, e.g. Cyclas, Pisidium; (c) single species, e.g. in the generally dioecious genera Ostrea, Pecten, Cardium.

δὐω, two; μόνος, single; γόνος, semen; πόρος, passage.

Von Brunn, Arch. Mikr. Anat. xxiii. p. 413.

Hist. Anim. v. 6 and 12, iv. 1, ed. Bekker, 1837.

‘On pourra constater si ce ne seraient pas des parties détachées de quelque céphalopode dans le but de servir à le fécondation,’ Hist. Nat. Helminthes, 1845, p. 482.

Steenstrup, Ann. Mag. Nat. Hist. (2), xx. p. 81 f.

C. Ashford, Journ. of Conch. iii. p. 239, iv. pp. 69, 108.

W. E. Collinge, Zoologist, 1890, p. 276.

Pelseneer, Comptes Rendus, cx. p. 1081.

Kon. Vet. Akad. Handl. 1848, pp. 329–435.

P. Z. S. 1891, p. 52 f.

The result of some experiments by Professor Herdman upon Littorina rudis, tends to show that it can live much better in air than in water, and goes far to support the view that the species may be undergoing, as we know many species must have undergone (see p. 20), a transition from a marine to a terrestrial life. It was found that marked specimens upon the rocks did not move their position for thirty-one successive days (Proc. Liverp. Biol. Soc. iv. 1890, p. 50).

Diminutive of κτείς, a comb.

Stoliezka, quoted in Journ. de Conch. xviii. p. 452.

ζύγος, a yoke, from the symmetrical position of the branchiae.

Pelseneer, ‘Challenger’ Reports, vol. xxiii. part lxvi.

Zoologist, xii. p. 4248.

Mollusques de France, i. p. 81.

N. Denk. Schw. Ges. xxix. (2) p. 196 f.

Bergh, Morph. Jahrb. x. p. 172.

P. Fischer, Journ. de Conch. ix. p. 101.

Bull. Mus. C. Z. Harv. xviii. p. 434.

Pelseneer, Comptes Rendus, cvi. p. 1029.

E.g. Kollmann, Zeit. wiss. Zool. xxvi. p. 87.

Proc. Roy. Soc. 1873, p. 70.

Griesbach (Arch. mikr. Anat. xxxvii. p. 22) finds haemoglobin in several bivalves, e.g. Poromya granulata, Tellinata planata, Arca Noae, and Pectunculus glycimeris.

Trans. Roy. Soc. N. S. Wales, xxii. p. 106.

Pelseneer, Comptes Rendus, cx. p. 154.

Science, iv. p. 50.

P. Fischer, Journ. de Conchyl. (3) xxvii. p. 201.

Journ. of Conch. vi. p. 349 ff.

Quart. Journ. Micr. Sc. N.S. xv. p. 37.

Ann. Mag. Nat. Hist. (2), xx. p. 336.

V. Willem (Arch. Biol. ut infr.) denies this, and declares that Cyclostoma is only very sensitive to movements. The present writer has often approached, with the greatest care, a crawling Cyclostoma, but it always withdrew into its shell or fell to the ground when approached within about 10 or 12 inches.

Arch. Biol. xii. 1892, p. 57.

‘Challenger’ Reports, Zoology, vol. xxvii. part lxxiv. p. 3.

Animal Life, p. 372 f.

Bergh, Morph. Jahrb. x. p. 172.

Ann. Mag. Nat. Hist. (5) xiv. p. 141.

The nature of the grouping of the eyes into rows varies considerably in different species. As a rule, the rows radiate from the beak, but occasionally they run parallel to the girdle. In Tonicia lineolata Fremb., they are grouped, as it were, under the shelter of strongly marked longitudinal wavy lines.

=Shell-Eyes in other Mollusca.=--The Rev. J. E. Tenison-Woods (Trans. Linn. Soc. N. S. Wales, xxii. p. 106) is of opinion that ‘shell-eyes’ are by no means confined to the Chitonidae, but that, in fact, multiplicity of eyes of this kind is the rule rather than the exception among the Mollusca. He finds (1) exceedingly minute and numerous ‘eyes’ on the outer surface of the shell in both univalves and bivalves; (2) large and solitary ‘eyes’ in the shell substance; (3) eyes on the mantle lobes in both univalves and bivalves; (4) eyes on the opercula.

Mitth. Stat. Zool. Neap. v. p. 447 ff.

W. Patten, Mitth. Zool. Stat. Neap. vi. (1886) pp. 546, 605 f.

Benderloch, p. 136.

Quart. Journ. Micr. Soc. xx. p. 443.

Quart. Journ. of Conch. i. p. 368.

British Conchology, i. p. xxviii.

Science Gossip, 1865, p. 259.

Mollusques de France, i. p. 130.

E.g. Sochaczewer, Zeits. wiss. Zool. xxxv. p. 30.

Zool. Anz. 1882, p. 472.

Zoologist, iv. p. 1266.

Journ. Mar. Biol. Ass. N.S. i. p. 217.

Moquin-Tandon, Moll. de France, i. p. 133.

Zool. Jahrb. Anat. iv. (1890) p. 501.

Baudon, Rév. Mag. Zool. 1852, p. 575.

Arch. Zool. Exp. Gén. (2) v. 1887, p. 2; compare also C. H. Hurst, Natural Science, ii. pp. 360, 421.

Compare Pelseneer, Bull. Sci. Fr. Belg. (3) xix. pp. 107, 182.

Pelseneer, Arch. Biol. viii. p. 723.

Also known as labial and supra-oesophageal ganglia.

Wivén, however (K. Sv. Vet. Ak. Handl. xxiv. 1892, No. 12), describes transverse connectives in Chaetoderma.

στρεπτός, twisted; εὐθύς, straight.

With the exception of Actaeon, which is streptoneurous (Bouvier, Comptes Rendus, cxvi. p. 68).

This fusion of the cerebral and pleural ganglia and the consequent union of the cerebro-pedal and pleuro-pedal commissures can be recognised by sections of the mass (Pelseneer, Comptes Rendus, cxi. p. 245).

There is practically no pharynx in the Pelecypoda, the mouth opening directly into the oesophagus.

Radere, to scrape; ὸδούς, tooth; φέρειν, to carry.

The mechanism of the radula has been dealt with by Geddes, Trans. Zool. Soc. x. p. 485. Rücker has observed (Ber. Oberhess. Gesell. Nat. Heilk. xxii. p. 207) that the radula in Helix pomatia is the product of five rows of cells; the use of the first row is uncertain, the second forms the membrane of the radula, while rows three to five originate the teeth.

Jahrb. Deut. Malak. Gesell. iii. p. 193.

The whole of the radulae and jaws figured in this work are taken from the original specimens in the collection of the Rev. Prof. H. M. Gwatkin, who has always been ready to give me the run of his cabinets, which probably contain the finest series of radulae in the world. To his kindness I owe the following description of the process of mounting: “The first step is to obtain the radula. Dissection is easy in species of a reasonable size. On opening the head from above, so as to lay open the floor of the mouth, the radula itself is seen in most of the marine species, though in others it is contained in a sort of proboscis; and in the Pulmonata and others the student will find the buccal mass, with commonly a brown mandible at its front end, and the lingual ribbon in its hinder part. The teeth may be recognised by their silvery whiteness, except in a few cases like Patella and Chiton, where they are of a deep brown colour. When obtained, the radula may be cleaned by boiling in a solution of caustic potash. There is no risk of injury if the solution is not too strong.

“Smaller species may be treated more summarily. The proboscis, the buccal mass, or even the whole animal may be thrown into the potash solution and boiled till scarcely anything is left but the cleaned radula. Remains of animals dried inside the shell may be similarly dealt with, after soaking in clean water. With a little care, this process will answer for shells down to the size of Ancylus or Rissoa. The very smallest (Carychium, Tornatellina, Skenea, etc.) must be crushed on the slide and boiled on it, after removing as much as possible of the broken shell. The radula can then be searched for under the microscope, and washed and mounted on the slide.

“The student must be warned that though the general process is simple, there are difficulties in particular cases. In the Pulmonata, for example, membranes on both sides of the radula need careful removal. Murex, Purpura, and most of the Taenioglossa have the side teeth folded down over the central, so that the arrangement is not well seen till they have been brushed back. The Cones, again, have no basal membrane at all, so that if the potash is not used with great care, the single teeth will fall asunder and be lost. Perhaps the worst case is where a large animal has a radula as small as that of a Rissoa, like Turritella, Harpa, or Struthiolaria, or where the radula is almost filmy in its transparency, like those of Actaeon and the small Scalaria.

“When once the radula is laid out, the mounting is commonly easy. Canada balsam makes it too transparent. Fluids may be used, and are almost necessary for thick radulae like those of large Chitons; but the best general medium is glycerine jelly. It runs under the cover glass by capillary attraction, and may be boiled (though only for a moment) to get rid of air bubbles. It should then be left unfinished for several weeks. If cracks appear, the reason is either that the jelly is a bad sample, or that it has been boiled too long, or (commonly) that the object is too thick; and there is not often any difficulty in remounting. I have no serious complaint of want of permanence against the medium, if I may speak from a pretty wide experience during the last twenty years.”

The substance both of the jaw and radula is neither crystalline nor cellular, but laminated. Chitin is the substance which forms the ligament in bivalves, the ‘pen’ in certain Cephalopoda, and the operculum in many univalves. Neither silica nor keratine enter into the composition of the radula.

τόξον, arrow; ῥάχις, ridge, sharp edge; ταινία, ribbon; πτηνός, winged; γυμνὀς, bare; ῥιπίς, fan; δοκός, beam.

V. concinna, according to Schacko (Conch. Mitth. i. p. 126, Pl. xxiv. f. 5); the lateral is large, strong, unicuspid on a broad base.

In some cases (e.g. Hyalinia inornata) the laterals are very few, while in Zonites laevigatus the first side tooth is more of a marginal than a lateral.

Semon, Biol. Centralbl. ix. p. 80.

According to Moquin-Tandon (Moll. de France, i. p. 44) this process in Bithynia is attached by one end to the wall of the stomach. Vivipara, with two jaw pieces, does not possess this stylet; Bithynia, which does possess it, has no jaw.

J. H. Vanstone, Journ. Linn. Soc. xxiv. p. 369.

Biol. Centralbl. vii. p. 683; SB. Ges. Nat. Fr. 1890, p. 42; Mag. Nat. Hist. (2) v. 1850, p. 14.

νεφρός, kidney.

Ann. Mag. Nat. Hist. (2) xvi. p. 298.

See, for instance, Quart. Journ. Conch. i. p. 340 (Cyl. Raveni): Jahrb. Deut. Malak. Gesell. 1879, p. 98 (Clausilia dubia).

Cailliaud, Journ. de Conchyl. vii. p. 231; Gassies, ibid. p. 44.

Arch. Naturgesch. xlii. p. 209.

Dr. W. B. Carpenter, Rep. Brit. Ass. xiii. p. 71; xiv. p. 1; xvii. p. 93; J. S. Bowerbank, Trans. Micr. Soc. i. p. 123; Ehrenbaum, Zeit. wiss. Zool. xli. p. 1.

See also p. 258.

J. E. Gray, Phil. Trans. 1833, p. 774 f.

J. E. Gray, Phil. Trans. 1833, p. 774 f.

Journ. de Conchyl. iv. p. 424.

Journ. de Conchyl. xii. p. 3.

T. Scott, Journ. of Conch., 1887, p. 230.

M. de Villepoix, Comptes Rendus, cxiii. p. 317.

Proc. Ac. Nat. Sc. Phil., 1892, p. 350.

Mr. B. B. Woodward has recently pointed out (P. Z. S. 1892, p. 528) a very remarkable method of shell absorption and growth in Velates and certain other Neritidae.

The only exception appears to be Pedipes, while in Cassidula and Scarabus the absorption is partial (Crosse and Fischer, Journ. de Conch. xxx. p. 177 f.).

Strombus and Pteroceras (see Fig. 99, p. 200) exceptionally develop a siphonal notch which is distinct from the anterior canal.

The columella, as distinct from the columella lip, is the solid pillar of shell round which the whorls are coiled (Fig. 177), the lower, or anterior portion of which alone is usually visible.

J. E. Gray, Phil. Trans. 1833, p. 812.

W. H. Dall, Amer. Journ. Sc. xxxviii. p. 445 f.

The term epidermis, as distinct from periostracum, is properly restricted to the outer layer of the skin of the mantle and body generally.

J. Lewis, Proc. Bost. Soc. vi. p. 149.

Journ. of Conch. v. p. 66.

The Dispersal of Shells, pp. 182–195.

E. A. Smith, P. Z. S. 1892, p. 259.

C. T. Musson, Proc. Linn. Soc. N. S. Wales (2), v. p. 883.

Scient. Results Sec. Yarkand Exped. “Mollusca,” pp. 1–16.

Mr. H. W. Kew, The Dispersal of Shells, has brought together a very large series.

The Naturalist in Nicaragua, p. 334 f.

Morelet, Journal de Conch. 1875, p. 194.

Pollonera, Boll. Mus. Zool. Torino, v. 1890, No. 87.

South and south-western France, however, belong to the Mediterranean Sub-region.

The coast-line of north-east China, including Corea and Japan to north Niphon, is much more definitely tropical than the adjacent inland districts. The coast-line, therefore, must be placed in the Oriental Region, while the inland districts belong to the Palaearctic Region.

Biol. Centralbl. ii. p. 208.

Craven, Journ. de Conchyl. (3) xxviii. p. 101.

Jahrb. Deutsch. Malak. Gesell. viii. p. 278.

Netchayeff, Kazan Soc. Nat. xvii. fasc. 5.

Fauna der Congerien-Schichten, p. 142.

Streptaxis is a remarkable instance of a mainland genus. Although abundant in the Oriental, Ethiopian, and Neotropical regions, it never seems to occur on any of the adjacent islands, except in the case of Trinidad (1 sp.), which is practically mainland. Omphalotropis, on the other hand, is the exact reverse of Streptaxis in this respect, occurring all over Polynesia and the Malay Is., as far west as Borneo, as well as on the Mascarenes, but never, save in a doubtful case from China, on the mainland of Asia, Australia, or Africa.

The Amboyna group has been much the better explored. Common to both groups are one sp. each of Kaliella, Trochomorpha, Opeas, Leptopoma, Cyclotus, Helicina.

A. H. Cooke, P. Z. S. 1892, pp. 447–469.

Mysol, with 2 Chloritis, 1 Insularia, 1 Cristigibba, is decidedly Papuan.

See especially C. Hedley, Note on the Relation of the Land Mollusca of Tasmania and New Zealand, Ann. Mag. Nat. Hist. (6) xiii. p. 442.

Hedley and Suter, Proc. Linn. Soc. N. S. Wales (2), vii. p. 613. Twenty-one species are “introduced.”

Nine species have been introduced: 6 from Europe, 2 from the West Indies, 1 from the Western Isles.

It is by no means implied that unbroken land communication between India and Madagascar, across the Indian Ocean, ever existed. A series of great islands, whose remains are attested by the Chagos and other banks, would be quite sufficient to account for the results, as we find them. See especially Medlicott and Blanford, Geology of India, vol. i. p. lxviii.

Journ. Cinc. Soc. Nat. Hist. iii. p. 317. The number is doubtless susceptible of very considerable reduction, say by one-half at least.

Simpson, Amer. Nat. xxvii. 1893, p. 354.

Compare von Martens, Malak. Blätt. 1868, p. 169; von Ihering, Nachr. Deutsch. Malak. Gesell. 1891, p. 93.

The distribution of some Pteropoda has been worked out by Munthe, Bih. Svensk. Ak. Handl. XII. iv. 2, by Pelseneer “Challenger” Rep., Zool. xxiii., and by Boas, Spolia Atlantica.

Bull. Mus. C. Z. Harv. xiv. p. 202; xxiii. p. 34 f.

See papers in P. Z. S. 1878–85.

A break in this uniformity may be found underneath the course of a great oceanic current like the Gulf Stream, which rains upon the bottom a large amount of food. A. Agassiz (Bull. Mus. C. Z. Harv. xxi. p. 185 f.) explains in this way the richness of the fauna of the Gulf of Mexico as compared with that of the west coast of tropical America.

On the western coasts of Europe and America, where the change in surface temperature is very gradual, Purpura lapillus (the west American ‘species’ are at best only derivatives) is able to creep as far south as lat. 32° (Mogador) in the former case, and lat. 24° (Margarita Bay) in the latter, the mean annual temperature of the surface water being 66° off Mogador, with an extreme range of only 8°, and that of Margarita Bay 73°, with an extreme range of only 5°. On the eastern coasts, where the Pacific and Atlantic gulf-streams cause a sudden change of temperature, the Purpura is barred back at points many degrees farther north, viz. at lat. 41° (Hakodadi), surface temperature 52°, extreme range 25°; and at lat. 42° (Newhaven), surface temperature 52°, extreme range 30°.

E. A. Smith, P. Z. S. 1890, pp. 247, 317.

A. H. Cook, Ann. Mag. Nat. Hist. (5) xviii. (1886) p. 380 f; E. A. Smith, P. Z. S. 1891, p. 391 f.

C. Keller, Neue denksch. Schw. Gesell. xxviii. 1883, pt. 3.

According to Tate (Trans. Roy. Soc. S. Austr. 1887–88, p. 70), ‘Australian’ species predominate at Freemantle (32°), but Tenison-Woods (J. Roy. Soc. N. S. Wales, xxii. p. 106) holds that the tropical fauna extends as far south as Cape Leeuwin (34°), and that the Australian forms are not predominant until the extreme south. Tenison-Woods regards Cape Byron (31°) as the limit of the tropical fauna on the east coast, while some characteristic tropical genera reach Port Jackson, and a few (e.g. Cypraea annulus) Tasmania.

A full account of the distribution of Voluta is given by Crosse, Journ. de Conchyl. (3) xix. p. 263.

Usually known as ‘Patagonian,’ but since the Magellanic Sub-region includes a considerable part of Patagonia, and since the greater part of sub-region (6) lies out of Patagonia, it has been thought advisable to change the name.

Amer. Nat. xx. p. 931.

W. H. Dall, Proc. Biol. Soc. Washington, v. p. 1 f.

Trans. Connect. Acad. v. p. 177; Zoologist, 1875, p. 4502.

Rep. Scotch Fish. iii. 1885, App. F, p. 67.

Nautilus, vi. 1892, p. 82.

Journ. Mar. Zool. i. pp. 3, 9.

Rep. Brit. Assoc. 1844, Transactions, p. 74; P. Z. S. 1839, p. 35.

It is convenient, but not morphologically correct, to apply the terms ‘ventral’ and ‘dorsal’ in this sense.

φραγμός, partition; σήπιον, cuttle-bone; χόνδρος, long cartilage.

μυέω, close the eyes; ὕψις, sight; contrasted with Oigopsidae (οἰγω, open).

The classification is that of Foord, Catal. Fossil Cephal. Brit. Mus., 1888.

Saville Kent, Proc. Roy. Soc. Queensland, vi. p. 229.

J. Power, Ann. Mag. N. H. (2) xx. p. 334; P. Z. S. 1836, p. 113; Arch. Zool. Exp. Gén. (3) i. 1893, p. 105.

In deference to Bergh’s high authority, the position of a sub-order is here given to the Ascoglossa. It may be doubted whether that position will stand the test of further investigation, and whether the families concerned will not be added to the Cladohepatic Nudibranchs.

This family has also been classified with the Bulloidea and with the Aplysioidea.

It appears more convenient to treat the whole group together, rather than deal with the two sections separately.

An operculum is said to exist in the young forms of Auricula and Parmacella.

Proc. Ac. Philad. 1892, p. 390.

Compare Jackson, Amer. Nat. xxv. p. 11 f.

“A Monograph of the British Fossil Brachiopoda,” Palaeontographical Society, London, vols. i.-v. 1851–84.

Ibid. vol. vi. 1886.

“Contributions to the Anatomy of the Brachiopoda,” Proc. Roy. Soc., vol. vii.

“Untersuchungen über den anatomischen u. histologischen Bau der Brachiopoda Testicardinia,” Jenaische Zeitschrift, vol. xvi., 1883.

“On a living Spinose Rhynchonella from Japan,” Ann. Mag. Nat. Hist., 5th ser., vol. xvii., 1886

Loc. cit. p. 465.

Shipley, “On the Structure and Development of Argiope,” Mitt. aus d. Zool. Stat. zu Neap. Bd. iv. 1883.

Schulgin, “Argiope Kowalevskii,” Zeit. f. wiss. Zool. Bd. 41, 1885.

American Jour. of Sci. and Arts, 3rd series, vol. xvii. 1879.

Loc. cit. p. 470.

“Recherches sur l’Anat. des Brachiopodes Inarticules,” Arch. Zool. Exp. (2), Tome iv., 1886.

“Untersuchungen über den Bau der Brachiopoden,” Jena, 1892.

“Vorläufige Mittheilungen über Brachiopoden,” Zool. Anz. Bd. viii. 1885.

Hancock’s nomenclature is here used. The corresponding names used by King and Brooks are placed in brackets. Their nomenclature is used by many palaeontologists, and is adopted in Fig. 322.

Development of the Brachiopoda, 1873 (Russian).

“Histoire de la Thécidie,” Ann. d. Sci. Nat., Sér. 4, vol. xv., 1861.

“On the Early Stages of Terebratulina septentrionalis,” Mem. Boston Soc. Nat. Hist., vol. ii., 1869. “On the Development of Terebratulina,” Ibid. vol. iii., 1873.

“Choses de Nouméa,” Arch. d. Zool. exp. et gen., 2nd ser., vol. ix., 1891.

J. Barrande, Syst. Silur. Bohème, vol. v., 1879. Hall and Clarke, Introd. Palaeozoic. Brach. (Palaeont. of New York, 1892–1894). Davidson, Monogr. Brit. Foss. Brach. (Palaeont. Soc., 1851–1884). Waagen, Salt Range Fossils (Mem. Geol. Surv. India, 1879–1885).

The results of the investigations of King (Ann. Mag. Nat. Hist., 4th ser., vol. xii., 1873) and of Brooks (Chesapeake Zool. Laboratory, Scientific Results, p. 35, 1879), and the simple nomenclature of these authors are here followed in preference to those of others, owing to the difference of opinion amongst anatomists of the functions and homologies of the muscles. The lateral muscles enable the valves to move backwards and forwards on each other; the centrals close the shell; the umbonals open it; and the transmedians allow a sliding sideways movement of one valve across the other (see also p. 477).

Davidson and King, Quart. Jour. Geol. Soc., xxx. (1874), p. 124.

Amer. Jour. Science, 1890–1893.

Transcriber’s Notes:

1. Obvious printers’, punctuation and spelling errors have been corrected silently.

2. Where hyphenation is in doubt, it has been retained as in the original.

3. Some hyphenated and non-hyphenated versions of the same words have been retained as in the original.

4. Superscripts are represented using the caret character, e.g. D^r. or X^{xx}.

5. Italics are shown as xxx.

6. Bold print is shown as =xxx=.