Part 70

SOLENOCURTUS. Bl. (Solen and curtus, short.) Fam. Pyloridea, Bl. Solenacea, Lam.--Descr. Oval, elongated, equivalve, sub-equilateral, with the edges nearly straight and parallel, and the extremities rather truncated; umbones not very prominent, sub-central; hinge with or without two or three rudimentary cardinal teeth; ligament prominent, placed upon thick callosities; muscular impressions two, distant, rounded; palleal impression straight, with a deep sinus. East Indies--Obs. Distinguished from the true Solenes by the central position of the umbones and an internal bar reaching partly across the shell.

SOLETELLINA. Bl. SANGUINOLARIA radiata. S. Diphos, f. 99. S. livida of Sowerby, and similar species, are placed together in this genus.

SPATHA. Lea. A sub-genus of IRIDINÆ, consisting of I. rubens and I. nilotica, which have not distinctly crenulated margins. Spatha solenoides, of Lea, is the genus Mycetopus D'Orbigny. Fig. 151.

SPHÆNIA. Turt. A genus consisting of a small species resembling Saxicava, in general appearance, but having a spoon-shaped process on the hinge of one valve. S. Binghamii, Fig. 96.

SPHÆROIDINA. D'Orb. A genus of microscopic Foraminifera.

SPHÆRULACEA. Bl. The first family of Cellulacea consisting of the following genera of microscopic Foraminifera: Miliola, Melonia, Saracenaria, Textularia.

SPHÆRULACEA. Lam. The fourth family of Cephalopoda, Lam. described as multilocular, globular, sphærical, or oval, with the whorls enveloping each other; some of them have a particular internal cavity, and are composed of a series of elongated, straight and contiguous chambers which altogether form a covering for the internal cavity. This family contains the genera Miliola, Gyrogona and Melonia.

SPHÆRULITES. Lam. (Sphæra, a sphere.) Fam. Rudistes, Lam. and Bl.--Descr. Orbicular, inequivalve, irregularly foliated outside; lower valve cup-shaped, depressed; upper valve nearly flat, like an operculum.--Obs. These fossils are not regarded as shells by all conchologists. S. foliacea, Fig. 193.

SPHINCTERULUS. Montf. LENTICULINA, Bl. A genus of microscopic Foraminifera.

SPINES. (Spina, a thorn.) Thin, pointed spikes.

SPINOSE. (Spinosus.) Having spines or elevated points, as Neritina spinosa. Fig. 325.

SPIRAL. (Spira, a spire.) Revolving outwards from a central apex or nucleus, like the spring of a watch. A shell or an operculum, may be spiral, without being produced into a pyramid. Bands of colour, striæ, grooves, &c. commencing from the nucleus and following the volutions of the shell, are described by the above word.

SPIRAMILLA. Bl. A genus of Serpulacea, differing from other Serpulæ principally in the characters of the animal.

SPIRATELLA. Bl. LIMACINEA, Lam. Fig. 224.

SPIRE. (Spira.) The cone or pyramid produced in a non-symmetrical univalve by its oblique revolution downwards from the apex or nucleus. The spire, in descriptions, includes all the volutions above the aperture. See Introduction.

SPIRIFER. Sow. (Spira, a spire; fero, to bear.) Order, Brachiopoda, Lam.--Descr. Transverse, equilateral; hinge linear, straight, widely extended on both sides of the umbones, which are separated by a flat area in the upper and larger valve; this area is divided in the centre by a triangular pit for the passage of the byssus; interior with two spirally convolute appendages.--Obs. This genus, which is only known in a fossil state, is distinguished from Terebratula externally, by the flat area in one valve, internally, by the singular spiral process from which the above name is derived. Fig. 214, 215. Most of the species belong to the mountain or carboniferous limestone.

SPIROGLYPHUS. Daud. A genus consisting of a species of Serpula Auct. which makes a groove for itself in the surface of shells. Serpula spirorbis, var. Dillwyn. Fig. 8.

SPIROLINA. Lam. A genus of microscopic Foraminifera.

SPIROLOCULINA. D'Orb. A genus of microscopic Foraminifera.

SPIRORBIS. Lam. A genus composed of species of SERPULA, Auct. which are coiled round in a spiral disc like a snake at rest. S. nautiloides, fig. 5, is the common little white shell, found upon the shell of lobsters.

SPIRULA. (Spira, a winding compass.) Fam. Lituolata, Lam. Lituacea, Bl.--Descr. Convolute, smooth, symmetrical, discoid, with parallel unconnected whorls, divided into numerous chambers by transverse septa; siphon continuous.--Obs. This pretty little shell is partly internal, only a part of it being visible when on the animal. Fig. 471.

SPISULA. Gray. A genus composed of MACTRA fragilis, and other similar species, which have the ligament sub-external, marginal, not separate from the cartilage; with the posterior lateral teeth double in one valve, and single in the other. M. fragilis, fig. 80, is the species figured for Spisula in Mr. Gray's paper on the Mactradæ, in the second series of Loudon's Magazine of Natural History. We have since learned, however, that it was figured there by mistake, not having been intended for a Spisula, but belonging more properly to the genus Mactra, as defined by Mr. Gray, whose description of Spisula, is as follows:--"Shell ovate, trigonal, sub-angular at each end. Hinge and lateral teeth as in Mactra, but hinge of left tooth small. Siphonal inflexion ovate." The principal difference between Spisula and Mactra is, that the ligament is not separated from the cartilage in the former.

SPONDYLUS. Auct. (A shell-fish, Ancients.) Fam. Pectenides, Lam. Sub-ostracea, Bl.--Descr. Inequivalve, sub-equilateral, irregularly foliaceous and spinose, auriculated, denticulated at the margins, attached by the lower and deeper valve; hinge rectilinear, with two prominent teeth in each valve, locking into corresponding cavities in the opposite valve; umbones separated by a broad, elongated, triangular disc in the lower valve; ligament contained in a groove, dividing the triangular area in the centre; muscular impressions one in each valve, sub-central, sub-orbicular. The Mediterranean, East and West Indies, and China, produce Spondyli most abundantly.--Obs. This genus is remarkable for the richness and beauty of the spines and foliations, which adorn the external surface of most of the species, the splendid colours by which many of them are varied, and the natural groupings formed by their attachment to each other. Fig. 177, and Frontispiece.

SPORULUS. Montf. A genus of microscopic Foraminifera.

SQUAMOSE. (Squama, a scale.) Scaly, covered with scales, as the pedicle of Pollicipes Mitellus, fig. 37*.

STENOPUS. Guild. ([Greek: Stenos], narrow, [Greek: pous], foot.) A genus nearly "allied to the Linnæan Helices, from all of which it differs in the curious contraction of the pedal disc, and the caudal tentaculum furnished with a gland beneath." The shell is described as heliciform, umbilicated, transparent, with the aperture transverse. The two species described are Stenopus cruentatus and lividus; they are both from the Caribbæan Islands, Guild. Zool. Journ. xii. p. 528, tab. 15, f. 1 to 5.

STOMATELLA. Lam. See STOMATIA.

STOMATIA. Auct. ([Greek: stoma], stoma, mouth.) Fam. Macrostomata, Lam.--Descr. Sub-orbicular, oblong, auriform, variegated without, iridescent within; spire depressed; aperture entire, very wide, oblique; peritreme uninterrupted. Obs. This genus is known from Haliotis by being destitute of the series of holes; is distinguished from Sigaretus by the substance of the shell, the latter being internal, and never pearly. Our description includes STOMATELLA, Lam. The Stomatiæ are marine, and belong to the East Indies and New Holland. Fig. 335, S. Phymotis.