Part 49

MULINIA. Gray. A genus composed of species of MACTRA, Auct. described as having the ligament (properly so called) internal, and lateral teeth simple. Ex. fig. 82. M. bicolor; Mactra, Auct.

MULLERIA. Fer. Fam. Ostracea, Lam.--Descr. Irregular, subquadrate, inequivalve, inequilateral, foliaceous, attached, pearly within, green, horny without; hinge irregular, with a partly external ligament, passing to the interior, through a sort of sinus.--Obs. This remarkable shell resembles Etheria in general form and appearance, but is distinguished by having only one muscular impression. It is so rare that, although not very beautiful, a specimen has been known to produce £20. at a sale. Fig. 192.

MULTILOCULAR. Many chambered.

MULTISPIRAL. (Multus, many, spira, spire.) A term applied to a shell when the spire consists of numerous whorls; or to an operculum of numerous volutions.

MULTIVALVE. (Multus, many; valva, valve.) Consisting of numerous valves. There are three kinds of multivalve shells: 1st. Those in which the valves are arranged in pairs, and produce a flattened figure, as Pedunculated Cirripedes, fig. 34 to 43; 2nd. Those in which they are arranged circularly, as Sessile Cirripedes, the valves of which are of two kinds; the opercular, consisting of several valves, which close the aperture, and the parietal, consisting of those which surround the body of the animal in a circular form, fig. 14 to 33. 3rd. Those in which they are arranged in a straight line, as Chiton, fig. 227.

MUREX. Auct. (A sharp rock.) Fam. Canalifera, Lam. siphonostoma, Bl.--Descr. Turrited, ventricose, thick, with three or more longitudinal, continuous, branched, spinose or fringed varices; spire prominent, acute; aperture oval, terminating in a posterior, partly closed canal, outer lip varicose, inner lip smooth, laminar; operculum horny, concentric, pointed.--Obs. This genus contains some of the most exquisitely beautiful shells in existence, the richness of their colouring, the ramifications of their varices, would render most species the finest possible subject for the exercise of the painter's art in still life. The most remarkable are the Rosebud Murex, with its pink-tipt fringes, the Venus Comb, with its long rows of parallel spines; the Ducal Murex, the Royal Murex, and many others, which are much sought after by collectors. Murex may be distinguished from Triton by the continuity of the varices, which follow each other in a tortuous direction on the spire. The Ranellæ have only two rows of varices, and have a posterior as well as anterior canal; while Murices have three or more varices, and only one canal. The genus Typhis consists of several small species resembling Murex in every respect, excepting that of having a tubular opening on the upper part of the whorl between each varix. See TYPHIS. The most beautiful Murices are brought from tropical climates. Fig. 395, 396.

MURICANTHUS. Sw. A sub-genus of Murex, thus described: "Varices numerous, foliated; spire short; margin of the outer lip with a prominent tooth near the base; Radix. Sw. Zool. Ill. 2nd series. pl. 113, Melanomathus. En. Méth. 418. f. 2." Sw. p. 296. The latter of the two species quoted, however, does not agree with the description, having no prominent tooth on the margin of the outer lip.

MURICATED. (Muricatus.) Having sharp points or prickles.

MURICIDEA. Sw. A genus of "Muricinæ," Sw. thus described, "Spire more produced, as long or longer than the body whorl; varices numerous; no internal channel at the top of the aperture." Sw. p. 297, and consisting of the following incongruous species, "Lamellosa. Chem. f. 1823, 4. magellanica. En. M. 419. f. 4. peruviana. Ib. f. 5. senticosa, Ib. f. 3. scaber. En. Méth. 419. f. 6. hexagona. Ib. 418. f. 3. erinacea. Mart. f. 1026." Sw. p. 297.

MUSCULAR IMPRESSIONS are the marks or areas formed on the interior surface of shells by the muscular fibres which attach the animals to them. Lamarck has divided his Conchifera into two kinds: 1st. Monomyaria, those which have but one adductor muscle, and consequently have but one impression in each valve, as the common Oyster, fig. 180; 2nd. The Dimyaria, those which have two, and consequently have two impressions in each valve. There are other smaller impressions in some shells besides the principal. The palleal impression is a mark or scar passing near the margin of the shell. See Introduction.

MYA. Auct. Fam. Myaria, Lam. Pyloridea, Bl.--Descr. Transverse, oval, thick, gaping at both extremities, rounded anteriorly, acuminated posteriorly; hinge with one large, dilate, compressed tooth in one valve, and a suture in the other, containing the cartilage; muscular impressions two, distant, large, irregular; palleal impression with a large sinus.--Obs. Mya may be known by the large, prominent, broad tooth in one valve. In Anatina there is one in each valve, and, in Lyonsia, accessory pieces. Lutraria has cardinal teeth and a ligamentary pit. Few species of Mya are known. They belong to the Northern Hemisphere. M. truncata, fig. 71.

MYCETOPODA or MYCETOPUS. D'Orb. Fam. Nayades, Lam.--Descr. Shell elongated, soleniform, inequivalve, inequilateral, gaping anteriorly; muscular impressions very complex.--Obs. These shells are said to terebrate like Pholas. Fig. 151. M. solenoides.

MYARIA. Lam. A family belonging to Lamarck's order Conchifera Dimyaria. Containing the following genera:

1. ANATINA. Ligament in a spoon-shaped prominence on the hinge of each valve, shell thin. Fig. 69.

2. MYA. Spoon-shaped prominence in one valve; shell thick. Fig. 71.

3. ANATINELLA. A spoon-shaped process in both valves. Fig. 70.

4. LYONSIA. An internal bony appendage on the hinge. Fig. 491, 492.

5. MYOCHAMA. Flat valve attached, a bony appendage on the hinge. Fig. 73.

6. CLEIDOTHÆRUS. Deep valve attached, a bony appendage. Fig. 75, 76.

7. CUMINGIA. Ligamentary pit in both valves, spoon-shaped. Fig. 87.

MYOCHAMA. Stutch. (Mya and Chama.) Fam. Myaria, Lam.--Descr. Inequivalve, irregular, attached, subequilateral; attached valve flat, with two marginal, diverging teeth, and one end of a little testaceous appendage fixed between them by a horny cartilage; free valve convex, with umbo incurved and two very minute, diverging teeth, between which the other end of the testaceous appendage is placed; external surface of both valves conforming to the grooves or undulations of the shell to which the specimen is attached; muscular impressions two in each valve; palleal impressions with a short sinus.--Obs. This new genus, of which only one species is known, the M. anomioides from New South Wales, differs from Anomia and Anatina in being attached by the surface of one of the valves, from which circumstance the word Chama is added to its name; the little testaceous appendage bringing it near the Myariæ. Fig. 73, M. anomioides.

MYOCONCHA. Sow. (Mya and Concha.) Fam. Cardiacea, Lam.--Descr. Oval, equivalve, oblique; umbones terminal; ventral margin rounded; hinge with an external ligament, and one oblique, elongated tooth in the left valve; impression of the mantle not sinuated.--Obs. The fossil genus has the general form of Mytilus or Modiola, but the hinge of the Conchæ generally.

MYOPARA. Lea. (Myoparo, a piratical oar-galley.) Fam. Arcacea, Lam. A genus founded on a minute fossil bivalve shell, somewhat resembling Isocardia in form, but having a series of teeth placed on each side of the umbones. M. costatus, fig. 135.

MYRISTICA. Sw. A genus of "Pyrulinæ," Sw. thus described: "Sub-pyriform; spire strong, spiny, or tuberculated, nearly as long as the base; umbilicus either partially or entirely concealed; inner lip vitreous, thin; the outer with an internal and ascending canal; the basal channel wide. Hippocastanea. En. M. 432. f. 4. lineata, Ib. f. 5. melongena. En. Méth. 435. f. 3. nodosa. Chem. 1564. 5." Sw. p. 307. Ex. P. Melongena, Fig.

MYRTEA. Turt. VENUS spinifera, Auct. LUCINA spinifera, Nonnull. The shells of this genus are described as "Oval, triangular, equivalve, nearly equilateral, closed. Hinge of one valve with a single tooth, and lateral one on each side; of the other valve with two teeth, the lateral ones obscure. Ligament external." British Channel and Mediterranean.

MYSCA. Turt. A genus composed of species of UNIO, Auct. which are distinguished by having "strong, transverse, notched, cardinal and long lateral teeth." Unio pictorum.

MYSIA. Leach. A genus composed of TELLINA rotundata, montagu and other similar species.

MYTILACEA. Bl. The fourth family of Lamellibranchiata, Bl. The shells are described as regular, equivalve, frequently with a thick, horny epidermis. A toothless hinge and a linear ligament. This family contains the genera Mytilus and Pinna.