A Conchological Manual by George Brettingham Sowerby (best interesting books to read txt) 📕

genus of small land shells

   with enamelled surface and spiral operculum. See PUPINA.

 

   MOURETIA. Gray. "_Gadin_," Adanson. A genus of patelliform shells,

   described as differing from SIPHONARIA (the original Mouretia of

   Adanson) in the situation of the siphon, which in Mouretia is close to

   the place where the muscular impression is interrupted to leave a space

   for the head; while in Siphonaria it is nearly half way between the

   anterior and posterior ends of the shell.

 

   MOUTH. The aperture or opening of univalve shells.

 

   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:

 

ANATINA. Ligament in a spoon-shaped prominence on the hinge of

       each valve, shell thin. Fig. 69.

 

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

 

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

 

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

 

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

       Fig. 73.

 

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

       76.

 

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.

 

   MYTILACEA. Lam. A family belonging to the first section of Conchifera

   Monomyaria, Lam. described as having the ligament partly interior,

   occupying the greater part of the hinge line, which is straight. The

   shell is rarely foliaceous. The Mytilaceæ cannot easily be confounded

   with the Malleaceæ, because the former are generally regular and the

   latter are irregular, and have a thick internal coating of pearl,

   beyond which the external coating extends. The genera may be thus

   distinguished:

 

MYTILUS. Umbones terminating in a point. Fig. 158.

 

DREISSINA. The same, with a septiform plate. Fig. 159.

 

MODIOLA. Anterior margin rounded beyond the umbones. Fig. 160.

 

PINNA. Open at the posterior extremity. Fig. 162.

 

LITHODOMUS. Cylindrical, living in holes. Fig. 161.

 

   MYTILUS. Auct. _Fam._ Mytilacea. Lam.--_Descr._ Equivalve, cuneiform,

   oblique, smooth, with umbones terminal, pointed, and posterior side

   broad, rounded; hinge linear, with a long, partly internal ligament;

   muscular impressions two in each valve, that on the posterior side

   large, irregular; that on the anterior small; palleal impression

   irregular.--_Obs._ The Linnean genus Mytilus included the Modiolæ,

   which differ from the Mytili in the rounded anterior side; and the

   Pinnæ, which are large shells, gaping at the posterior extremity. M.

   achatinus, fig. 158.

 

   NÆARA. Gray. A genus composed of ANATINA longirostrum, Lam. and other

   similar species.

 

   NAIA. Sw. A sub-genus of Castalia, Lam. thus described: "Oval, cardinal

   teeth beneath the bosses, and deeply sulcated, C. corrugata. _Lam._ En.

   Méth. 248. f. 8, picta. _Sw._ En. Méth. 248. f. 6." Sw. p. 379.

 

   NANINIA. Gray. A genus composed of the planorbicular species of HELIX,

   with large umbilici, and outer lip thin, included in the sub-genus

   Helicella, Fer. _Ex._ H. citrina, fig. 280.

 

   NASSA. Lam. A genus of small shells united to Buccinum by some authors,

   but separated by others on account of the little tooth-like projection

   terminating the columella. N. arcularia, fig. 423.

 

   NATICA. Brug. _Fam._ Neritacea, Lam. Hemicyclostomata, Bl.--_Descr._

   Globose, thick, generally smooth; spire short, pointed, with few

   volutions; aperture semilunar, entire; outer lip thin; columellar lip

   oblique, nearly straight, callous; umbilicus with a spiral callosity,

   terminating behind the columella, and sometimes filling up the cavity;

   operculum shelly in some species, horny in others; epidermis thin,

   light, semitransparent.--_Obs._ The straight, callous, smooth edge of

   the columella and the callosity serve to distinguish this genus from

   Nerita, Neritina, Neritopsis and Helix. Fig. 327, 328.

 

   NATICARIA. Sw. A sub-genus of Natica, thus described: "Oval; convex

   above; umbilicus small, open, placed very near the top of the aperture;

   inner lip reflected; small. N. melanostoma, Mart. 189. f. 1926, 1927.

   cancellata, _Sw._ Ib. 189. f. 1939. bifasciata, Griff. Cuv. 1. f. 2."

   Sw. p. 346.

 

   NATICELLA. Guild. A sub-genus of Natica, thus described: "Operculum

   horny; shell globose, but generally depressed; umbilicus nearly filled

   up by a vitreous deposition of the inner lip; spire obtuse. N.

   aurantia. Mart. 189. f. 1934, 1935." Sw. p. 345.

 

   NAVICELLA. Lam. (_A little ship._) _Fam._ Neritacea, Lam.

   Hemicyclostomata, Bl.--_Descr._ Transversely oval, symmetrical, smooth;

   aperture entire, oval; dorsal surface convex; outer lip thin; inner lip

   flat, straight edged; spread over the front surface of the body whorl,

   and sometimes hiding the apex; apex incurved; operculum testaceous,

   flat, sub-quadrate, with a lateral articulation.--_Obs_. This well

   known genus, of which there are several species, is named Cimber by

   Montfort. The shells are brought from India, the Isle of France and the

   Moluccas. Fig. 323, N. elliptica.

 

   NAUTELLIPSITES. Parkinson. A generic name proposed to include