Oval or oblong, fusiform; spire acute, sometimes elongated; aperture
oblong or oval, pyriform, with a distinct notch at the anterior
extremity; columella tortuous, callous, thickened at the extremity near
the spire; epidermis thick, horny, generally black.
Subtropical.--_Obs._ This description includes the two first species of
the genus Pirena, Lam. The Melanopsides are known from the Melaniæ by
the notch in the aperture. Fig. 315. M. costata.
MELAS. Montf. MELANIA, Auct.
MELATOMA. Sw. A sub-genus of Melanopsis. Sw. p. 341.
MELEAGRINA. Lam. MARGARITA. A genus composed of the Pearl Oyster and
similar species, separated from Avicula on account of the roundness of
their general form, but re-united by Sowerby. For generic characters,
see Avicula. Fig. 164. M. margaritifera.
MELEAGRIS. Montf. TURBO Pica, Auct. and similar species, having the
aperture oblique, the columella gliding imperceptibly into the outer
lip, and having an umbilicus.
MELINA. Schum. PERNA, Auct.
MELO. Brod. (_Melo_, a melon.) _Fam._ Columellaria, Lam.--_Descr._
Light, ventricose, oval, with a light greenish brown epidermis, spire
short, papillary, regular, sometimes hidden by the last whorl; aperture
large, nearly as long as the whole shell, emarginated anteriorly; outer
lip thin; columella slightly curved, with four or five laminar,
oblique, prominent plaits.--_Obs._ The genus Melo has been separated
from _Voluta_ principally on account of the largeness of the aperture,
the lightness of the shell and the thinness of the outer lip. Melo
differs from Cymba in the regularity of the spiral apex, and in the
greater rotundity of the shell. The Melons are beautifully coloured
large shells, found in the seas of the old world. The Melo Indicus has
a certain resemblance to a Melon. Fig. 435. M. Æthiopicus.
MELONIA or MELONITES. A genus of microscopic Foraminifera.
MERCENARIA. Schum. VENUS Mercenaria, Auct. The Money shell which passes
current for cash, under the name "Wampum," among the North American
Indians.
MERETRIX. Lam. Original name for Cytherea, Lam.
MEROE. Schum. CYTHEREA Meroe, sulcata, scripta, hians, Auct. and
similar species. Fig. 117, a.
MESODESMA. Desh. ERYCINA, Lam. according to G. B. Sowerby.
MESOMPHYX. Rafinesque. A genus proposed to be separated from HELIX,
Auct.
MICROTOMA. Sw. A genus of "Purpurinæ," Sw. thus described, "Pillar very
broad and curving inwards; aperture effuse; the notch at the base small
and nearly obsolete; spire very short, patula. Mart. 69. f. 758, 759.
persica. En. Méth. 397. f. 1. unicolor. _Sw._ Chem. f. 1449. Sw. p.
301." Purpura Persica. Fig. 414.
MILIOLA. Lam. A genus of microscopic Foraminifera.
MISILUS. Montf. A genus of microscopic Foraminifera.
MITRA. Lam. (_Mitre._) _Fam._ Columellaria, Lam. Angyostomata;
Bl.--_Descr._ Oblong, thick, covered with a light brown epidermis;
spire long, turrited, acute; aperture emarginated anteriorly; outer lip
thickened; columella with several oblique, thick plaits.--_Obs._ The
pretty small shells composing this genus differ from Marginella, not
only in general form, but in the outer lip not being reflected. Some
species of Voluta, of a more elongated shape than the rest, present a
near approach to the most ventricose of the Mitræ. The apex of Mitra,
however, is always acute, while that of Voluta is generally papillary.
The aperture of the former is narrow and the inner lip thickened, the
contrary being the case with the latter. The shells of this genus are
varied in colouring which is generally rich; and also in form, some
being angulated, some plicated, some coronated and others smooth. The
species are mostly tropical; very few occur so far north as the
Mediterranean. Fossil species are numerous in the Eocene beds. Fig.
431. M. Plicaria. Fig. 432. Conohelix marmorata, Sw.
MITRELLA. Sw. A genus consisting of MITRA Fissurella, casta,
Olivæformis, and similar species, described as "Rather small;
olive-shaped; unequally fusiform; always smooth and polished, and
sometimes covered with an epidermis; base obtuse and effuse; spire
nearly or quite equal to the aperture; plaits of the pillar few,
oblique, and extending beyond the aperture, which is smooth
internally." Sw. p. 321. M. Fissurata, E. M. 371. f. 1. Olivarii, f. 2.
Dactylus. 372. f. 5. _Ex._ Mitra bicolor.
MITREOLA. Sw. A genus of "Mitranæ," Sw. thus described: "Small;
unequally fusiform; the base obtuse; inner lip, typically thickened,
inflected, and either toothed or tuberculated; plaits on the pillar
distinct, the inferior largest; tip of the spire sometimes papillary;
aperture without either striæ or groove." Sw. p. 320, M. Monodonta, M.
Terebellum. Zool. Illustr. II. 128. f. 1. f. 2.
MODIOLA. Lam. (_Modiola_, a little measure.) _Fam._ Mytilacea,
Lam.--_Descr._ Equivalve oblique, cuneiform, inequilateral, thin, with
the anterior side short and narrow, slightly gaping to admit the
passage of a byssus, and the posterior side elongated, broad,
sub-quadrate; hinge thin, toothless, rectilinear, with a long, partly
external ligament; muscular impressions two in each valve; palleal
impression irregular, not sinuated.--_Obs._ This genus differs from
Mytilus, to which the common muscle belongs, in the anterior margin
being rounded out beyond the umbo, which in Mytilus is terminal. The
Lithodomi may be known from this genus by their cylindrical form. Fig.
160, M. Tulipa.
MOLLUSCA. (From _Mollis_, soft.) The twelfth class of invertebrated
animals with univalve shells or none; divided into the following
orders: Pteropoda, Gasteropoda, Trachelipoda, Cephalopoda, Heteropoda,
fig. 220 to 488. The term mollusca is also used in a general sense to
include the classes Conchifera and Mollusca of Lamarck, corresponding
with the type Malacozoa of De Blainville.
MONEY COWRY. Cypræa Moneta, which passes current in some parts of
Africa and the East Indies.
MONILEA. Sw. A sub-genus of Monodonta. Sw. p. 352.
MONOCEROS. ([Greek: Monos], _monos_, single; [Greek: Keras], _ceras_,
horn.) _Fam._ Purpurifera, Lam.--_Descr._ Ovate, thick, covered with a
brown epidermis; spire short, consisting of few whorls; aperture
emarginated anteriorly; columella rather flat; outer lip thick, with a
prominent tooth near the extremity.--_Obs._ This genus resembles
Purpura, in every respect, except in having the tooth from which the
name is derived. A catalogue of 16 species by Mr. Sowerby, sen. is
published with figures of 14, in parts 58 to 67 of the Conchological
Illustrations by the author. The species belong to the South American
coasts of the Pacific Ocean.
MONOCONDYLÆA. D'Orb. A sub-genus of Uniones, described as equivalve,
inequilateral, sub-rotund or angulated; hinge consisting of a large,
obtuse, round cardinal tooth in each valve, with no lateral teeth.
Monocondylæ (Unio) Paraguayana, D'Orb. fig. 149.
MONODONTA. Lam. ODONTIS, Sow. A genus separated from Trochus, Auct. on
account of the tooth or notch with which the columella abruptly
terminates. M. labeo, fig. 366.
MONOICA. Bl. The second sub-class of the class Paracephalophora, Bl.
divided into the orders Pulmobranchiata, Chismobranchiata,
Monopleurobranchiata, in the first section; and Aporobranchiata,
Polybranchiata, Cyclobranchiata, Inferobranchiata, and
Nucleobranchiata, in the second.
MONOMYARIA. Lam. ([Greek: Monos], _monos_, single; [Greek: muon],
_myon_, muscle.) The second order of Conchifera, consisting of those
bivalve shells which have but _one_ principal muscular impression in
each valve. The Monomyaria are thus divided: First section, containing
the families Tridacnacea, Mytilacea, Malleacea; second section,
containing the families Pectinides, Ostracea; third section, containing
the families Rudistes, Brachiopoda.
MONOPLEUROBRANCHIATA. Bl. The second order of the first section of
Paracephalophora Monoica. Bl. The animals are described as having the
lungs branched, situated at the right side of the body and covered more
or less completely by the operculiform mantle, in which there is
sometimes enveloped either a flat or a more or less involute shell,
with a large entire aperture. They have either rudimentary or auricular
tentacula, or none. This order, which includes mollusca with haliotoid
or patelliform shells, is divided into the following families: _Fam._
1. Subaplysiacea; 2. Aplysiacea; 3. Patelloidea; 4. Acera.
MONOPTYGMA. Lea. A genus of small shells resembling Tornatella, but
having a strong, oblique fold in the centre of the columellar lip. M.
Elegans, fig. 344.
MONOTHALAMIA. ([Greek: Monos], _monos_, single; [Greek: thalamos],
_thalamos_, chamber.) The second division of Cephalopoda, Lam.
containing only one genus, namely Argonauta.
MONOTHYRA. A term used by Aristotle to designate spiral univalves.
MONOTIGMA. Gray. A genus founded on the species represented fig. 371.
It is a turrited shell, but we are unacquainted with the characters of
the genus.
MORIO. Montf. CASSIDARIA, Auct. C. Echinophora, fig. 407.
MOTHER OF PEARL. This beautiful substance, which is so much resorted to
for ornamental purposes, constitutes the thickened coating of the
internal surface of the shell named by scientific collectors,
Meleagrina Margaritifera, commonly called the Pearl Oyster, a young
specimen of which is figured (164) in our plates. The reason why this
substance is called mother-of-pearl is that the true pearls are
produced from its surface. They arise principally from accident or
disease, and are sometimes artificially produced by pricking through
the outside of the shell while the animal is living. The animal is
allowed to live until it has formed a pearl over the wounded part.
MOULINSIA. Grateloup. PUPINA, Vignard. A 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:
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.
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:
1. MYTILUS. Umbones terminating in a point. Fig. 158.
2. DREISSINA. The same, with a septiform plate. Fig. 159.
3. MODIOLA. Anterior margin rounded beyond the umbones. Fig. 160.
4. PINNA. Open at the posterior extremity. Fig. 162.
5. 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 such
species of Nautilus as have been compressed, so as to assume an oval
instead of a round form. The genus Ellipsolites of De Montfort consists
of species of Ammonites similarly deformed.
NAUTILACEA. Bl. The fifth family of Polythalamacea, Bl. the shells of
which are described as more or less discoidal, compressed,
symmetrically convolute; the last whorl much longer than the others;
which are entirely hidden beneath it and advancing beyond the last but
one, so as constantly to form a large oval aperture, which is always,
however, modified by the last whorl. The septa are united in the
greater number of instances and pierced by one or more (?) siphons.
This family contains the genera Orbulites, Nautilus, Polystomella and
Lenticulina.