Chapter III: Part 3

ANCULOSA. Say. _Fam._ Melaniana, Lam. Ellipsostomata, Bl. A genus
proposed to include some fresh-water shells resembling those of the
genus Melania, the difference between them being that the spire of
Anculosa is more depressed, and the anterior of the outer lip more
angulated than in Melania. On an examination of the different species,
however, it will be found that this is quite unsatisfactory, as a
generic distinction; because some of the species with short flattened
spires, have rounded, and others angulated apertures. North America. An
example of each is represented, fig. 314.

ANCYLUS. Geoffroy. _Fam._ Calyptracea, Lam. Otides, Bl.--_Descr._ Thin,
obliquely conical, patelliform; apex acute, turned sidewise and
backwards; aperture oval; margin simple.--_Obs._ Although the little
fresh-water shells described under this name, resemble those of the
genus Patella, the animals which produce them are nearly allied to the
Lymneanæ. And, it may also be observed, that the shells themselves
differ from Patella in not being quite symmetrical, having the apex
turned on one side. A. fluviatilis, fig. 246. Found in Great Britain,
and in Southern and Central Europe, West Indies, &c.

ANDROMEDES. Montf. VORTICIALIS, Lam. _Fam._ Nautilacea, Lam. A genus of
microscopic Foraminifera.

ANGULATED. (Angulatus.) Having an angle, or corner, as the anterior of
the aperture of Eulima, fig. 348; the posterior side of Castalia, fig.
140; the whorls of Carocolla, fig. 277.

ANGULITES. Montf. A genus composed of species of fossil NAUTILI,
described by De Blainville as not umbilicated, with a dorsal keel and
angular aperture. NAUTILUS triangularis Buffon.

ANGIOSTOMATA. Bl. The third family of Siphonobranchiata, Bl. described
as differing little from the family of Entomostomata, but having long,
narrow, straight apertures, and the columellar lips straight or nearly
so. Were it not for the admission of the genus Strombus into this
family, it would correspond with COLUMELLARIA and CONVOLUTÆ of Lamarck.

ANNELIDES. The ninth class of invertebrated animals, divided into three
orders, namely, A. Apodes, A. Antennés, and A. Sedentaires. The last
only contains families of testaceous Mollusca. The animals are
vermicular, some naked, others inhabiting shelly tubes. See SEDENTARY
ANNELIDES.

ANNULAR OPERCULUM is one which has the nucleus central, or nearly so,
the other layers surrounding it in flattened rings. The term concentric
is also applied. See Introduction.

ANNULATED. (Annus, a ring.) Composed of, or surrounded by rings, as in
the case of Tubicinella, fig. 14.

ANODON. Brug. _Fam._ Submytilacea, Bl. Nayades, Lam. A genus composed
of such species of NAYADES as are destitute of teeth on the hinge.
Europe, North America, &c. An example is given in A. Cataractus, fig.
152.

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

ANOMIA. _Fam._ Ostracea, Lam. and Bl.--_Descr._ Irregular, inequivalve,
sub-equilateral, foliaceous, pearly within; adhering to marine
substances by means of a bony appendage, which passes through a large
circular opening in the lower valve; muscular impression divided into
three irregular portions; hinge destitute of teeth with a short
cartilage.--_Obs._ The Linnæan genus included not only the shells to
which the description above given would apply, but also many other
genera, such as Crania, Orbicula, Terebratula, &c. which belong to the
Brachiopoda, and are perfectly distinct. The Anomiæ are found in
Europe, N. America, Moluccas, Philippine Islands, &c. Fig. 186, in the
plates, is a somewhat reduced representation of a full grown specimen
of A. Ephippium. Fig. 187, the hinge of the under valve, with the bony
process. Fig. 188, the hinge showing the opening through which it
passes.

ANOSTOMA. See ANASTOMA.

ANSATES. Klein. A genus formed of those species of Patella which have a
produced, recurved beak. Helcion, Montf. _Ex._ Patella pellucida, fig.
230.

ANSULUS or ANSYLUS. Mr. Gray conjectures that the name of the genus
Ancylus, should be so written.

ANTENOR. Montf. A genus of microscopic Foraminifera.

ANTERIOR. In Bivalves is the side on which the head, or part analogous
to the head of the animal lies; it is known in the shell by the
umbones, which if turned at all, are turned towards that part. If there
be a sinus in the impression of the mantle, it is always on the
posterior part of the shell. If the ligament be placed only on one side
of the umbones, it is only on the posterior side. The anterior of a
_spiral univalve_ is that part of the outer lip which is at the
greatest distance from the apex. Of a _symmetrical_ conical univalve
such as Patella, it is that part where the head of the animal lies,
indicated by the interruption of the muscular impression. Of
_cirripedes_, that part where the ciliæ protrude are anterior; of
_Brachiopoda_, that part which is farthest from the umbones and which
corresponds with the ventral margin in other Bivalves. The anterior of
_symmetrical, convolute univalves_, is the outer or dorsal part of the
aperture, or that part which is farthest from the spire. Lamarck and
other Conchological writers have occasioned much confusion by their
errors on this subject; describing the same part of a shell at one time
anterior, at another posterior; but generally the reverse of the above
arrangement, which is founded upon the natural position of the animal,
and generally adopted. The anterior will be indicated by the letter
_a_, in figs. 119, 421, 229, 34, 202.

ANTIGONA. Schum. A genus composed of VENUS cancellata, Lam. (fig. 119.)
and similar species.

ANTIQUATED. This word, signifying _out of date_, is occasionally used
to express that species of composition which constantly occurs in
shells, by each fresh deposit or layer of calcareous matter, forming a
new margin, which being replaced by its successor, is no longer used as
the margin, and is consequently said to be out of date.

APEX. This term does not apply to the natural position of a shell, but
is used in a mathematical sense, to indicate the nucleus or first
formed part; which may be considered as the point of the spiral cone.
From this point, the shell enlarging rapidly or slowly as it descends,
takes a spiral, arched, straight, oblique, convolute, or irregularly
spiral course. The apex will be indicated by the letter _a_, in fig.
282 and 466.

APERTURE or MOUTH. The entrance to the spiral cavity of univalve
shells. The parts of the aperture are separately described, as follows:
The inner lip or labium is that part which lies over the preceding
whorl of the shell. It terminates anteriorly, or towards the lower part
in what is termed the columella, so called because it forms a kind of
axis on which the volutions turn. The outer lip, sometimes called the
labrum, is on the opposite side, or the farthest from the axis. If the
edges of the inner and outer lips unite all round, they are described
as composing the peritrême. In fig. 318, the aperture is marked by the
letter a.

APHRODITA. Lea. (from [Greek: Aphroditê], Greek name of Venus.) A genus
composed of CARDIUM Groenlandicum, Auct. fig. 123*, and other similar
species of Cardium, the teeth of which are either wholly wanting, or
very indistinct. Northern Ocean.

APICIAL. Belonging to the apex. The apicial extremity of the aperture
of a univalve shell, is that which is nearest to the apex of the spire.

APICULUM. Humph. TROCHUS, Lam.

APLEUROTIS. Rafinesque. A genus unfigured and imperfectly described as
differing in some respects from Terebratula and other Brachiopodæ.

APLEXUS. Fleming. A genus composed of PHYSA Hypnorum, Drap. &c. and
described as having the inner lip simple, and not spread over the body
whorl.

APLODON. Rafinesque. A genus proposed to be established at the expense
of the genus HELIX, but upon what grounds does not appear from the
imperfect description which is unaccompanied by a figure.

APLUSTRE. Schum. A genus formed for the reception of those species of
BULLA which have the spire uncovered. _Ex._ Bulla Aplustre,
(_aplustre_, a flag.) Auct. fig. 289.

APLYSIA. Linn. (_a_, without; [Greek: Pluô], to wash.) _Fam._
Laplysiens, Lam. Aplysiana, Bl.--_Descr._ Horny, transparent,
clypeiform, or shield-shaped, placed horizontally on the back of the
animal, with its convex side uppermost; apex slightly incurved.--_Obs._
The animal producing this shell has derived its name from the purplish
liquor which it exudes, when disturbed. In contour, it has been fancied
to present a certain likeness to a hare crouching, and on this account
was called _Lepus marinus_, or sea hare, by the ancients. The shell
bears a strong resemblance to Dolabella, which, however, is much
thicker, and more testaceous. The species are found in the
Mediterranean, European, and West Indian Seas. A. Petersoni, fig. 254.

APLYSIACEA. Bl. The second family of the order Monopleurobranchiata,
Bl. The animals composing this family are either destitute of shells,
or are provided with internal ones, which are flat, open, oblique, with
the apex or nucleus slightly incurved, not distinctly spiral. This
family contains the genera, Aplysia and Dolabella. The first
sub-spiral, with the apex terminal; shell thin, horny. Fig. 254. The
second the same, but thick and shelly. Fig. 255.

APOLLON. Montf. RANELLA Ranina, Auct. Placed by De Blainville in that
division of Ranella, which is characterized as being umbilicated. Fig.
393.

APOROBRANCHIATA. Bl. The first order of the second section of
Paracephalophora Monoica, Bl. The Thecosmata is the only family of this
order containing any approach to shells, these are Hyalæa and Cymbulia.

APORRHAIS. Petiver. A genus formed of ROSTELLARIA Pes-pelicani, _Auct._
(fig. 404) and similar species. Although the shell presents no
characters to distinguish it generically from Rostellaria, those who
have examined the soft parts are convinced that it is distinct. Of the
three species now known and figured in part I. of Thesaurus
Conchyliorum, by the Author, one is common on our own coast, and in the
Mediterranean; also North America. See ROSTELLARIA.

AQUATIC. A term applied by some authors to those species of Molluscous
animals, which inhabit fresh water, either in rivers, or salt water
standing pools, as distinguished from the marine or Mollusca. See
Fresh-water.

AQUILLUS. Montf. TRITON Lampas, Cutaceus, &c. Auct. Placed by De
Blainville in the division of the genus Triton, which is described as
having a short spire, being covered with tubercles and umbilicated.
Triton Cutaceus, fig. 399.

ARCA. Auct. (Anglicè, a boat.) _Fam._ Arcacea, Lam.--_Descr._ Obliquely
transverse, subquadrate, equivalve, or nearly so, inequilateral, thick,
ventricose, longitudinally ribbed, dentated near the inner margins;
hinge rectilinear, forming a flat, external area, upon which the
ligament is spread in cross rows, and having a series of small, regular
teeth, extending on both sides of the umbones in each valve; muscular
impressions distant.--_Obs._ The shells composing this genus are easily
distinguished from those of all other bivalve shells, by the straight,
linear row of small, notched teeth, and by the area between the
umbones. The genus _Cucullæa_ makes the nearest approach to it in this
respect, but it may easily be known from it by the outermost teeth on
each side of the row being oblique, and lengthened out; and also by the
prominent edge of the muscular impression. These shells are found
recent, in various marine localities; fossil, in the tertiary deposits.
The Arca Noæ, formerly regarded as the type of this genus, has, with
several other species, been separated from it under the name of
Bysso-arca, by Swainson, on account of an hiatus in the ventral margin,
to admit the passage of a byssus; this is not found in the true Arcæ.
The true Arcæ are mostly tropical. Arca Antiquata, fig. 131. Bysso-arca
Noæ, 132.

ARCACEA. Lam. A family of the order Conchifera Dimyaria, characterized
by a series of teeth placed on the hinge in a line. The genera may be
distinguished as follows,

1. ARCA. Hinge straight; valves close. Fig. 131.

2. BYSSO-ARCA. Valves gaping. Fig. 132.

3. CUCULLÆA. Distant teeth oblique; posterior muscular impression
prominent. Fig. 133.

4. PECTUNCULUS. Hinge curved. Fig. 134.

5. NUCULA. The same, with a pit in the centre of the hinge,
including Myopara and Crenella. Figs. 135 to 137.

6. SOLENELLA. Fresh water, oval; a series of teeth on one side of
the hinge, only two or three on the other. Fig. 138.

ARCHAIAS. Montf. A genus of microscopic Foraminifera.

ARCHONTE. Montf. HYALÆA, Auct.

ARCINELLA. Schum. CHAMA Arcinella, Auct.

ARCTICA. Schum. CYPRINA Icelandica, Auct.

ARCUATED. (Arcus, an arch.) Bent in the form of an arch, as Dentalium,
fig. 2.

AREA. A flat space or disc, on any part of a shell. As for instance,
the triangular space on the hinge of Arca, fig. 132, and Spondylus.

ARENACEOUS. (Arena, sand.) Of a sandy texture, as the sand tubes
surrounding the bodies of some of the Annellides, named Arenaria on
this account. But the word is more commonly used to intimate the habits
of the animal, burrowing with its shell in the sand.

ARETHUSA. Montf. A genus of microscopic Foraminifera.

ARGONAUTA. Auct. Commonly called the "Paper Sailor." _Fam._ Pteropoda,
Bl. _Order_ Cephalopoda Monothalamia, Lam.--_Descr._ Light, thin,
transparent or nearly so, symmetrically convolute, carinated by a
double row of tubercles, terminating smooth or tuberculated ribs
radiating towards the centre; aperture large, elongated; peritrême
acute, interrupted by the body whorl.--_Obs._ The exquisitely
beautiful, light and delicate fabrics included under the above name are
inhabited by a molluscous animal named the _Ocythöe_, which is provided
with tuberculated arms. These, hanging over the sides of the aperture,
give to the whole the appearance of a vessel propelled by oars: a
poetical illusion further heightened by the broad, flat membranes of
the two arms, which, when vertically expanded, present an idea of
sails. Pliny has described the Nautilus (the name has been changed by
the moderns) as sailing gracefully on the Mediterranean waters; and
Pope has versified the idea in the well known lines

"Learn of the little Nautilus to sail, Spread the thin oar and
catch the driving gale."

Scientific men have long been engaged in the interesting discussion,
whether the animal really belongs to the shell in which it is found, or
whether, having destroyed the rightful owner, it has possessed itself
of the "frail bark." It is now, however, proved beyond the shadow of a
doubt that the Argonaut is the testaceous part of the Ocythöe, and that
the broad membranes which in some representations have been
artificially placed as sails, are naturally bent backwards over the
shell like the mantle of some other molluscs. The interesting
experiments of Madame Power, in the Mediterranean, have contributed
very materially to lead the investigations of Naturalists to a
satisfactory conclusion. This lady kept a cage under water, in which
Argonautæ were bred in great numbers, giving her an opportunity of
tracing the gradual development of the shell in all its stages, from
the elastic and transparent nucleus to the full grown "Paper Sailor."
Fig. 485.

ARIANTA. Leach. A sub-genus of land shells, containing HELIX
arbustorum, Auct. (Gray, Turton, p. 137.)

ARION. A genus of slugs which have no shells.

ARROW-HEADS. One of the names by which fossils of the genus Belemnites
were formerly known.

ARTEMIS. A genus of bivalve shells, distinguished from those of the
genus Venus, by having a rounded, denticular form, and a deep, angular
sinus in the palleal impression. This does not appear to me to be a
sufficient ground of generic distinction, the palleal impressions of
the Veneres being subject to great variations. British, also from West
Indies, South America, Australia, &c. A. lincta, fig. 118.

ARTICULATED. (Jointed.) Applied to distinct parts of shells, which are
fitted or jointed into each other, as the valves of Chitones and those
of Balani. The operculum of Nerita is said to be _articulated_ to the
columella, having a small process by which it is as it were locked
under the edge. See _Introduction_. The word is also applied to the
Cirri, which protrude from the oral openings of Cirripedes.

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

ASIPHONIBRANCHIATA. Bl. The second order of Paracephalophora Dioica,
Bl. Consisting of spiral univalves, which have no notch or canal at the
anterior part of the aperture. This order is divided into the families
Goniosomata, Cricosomata, Ellipsostomata, Hemicyclostomata, and
Oxystomata.

ASPERGILLUM. Lam. (From _Aspergo_, to sprinkle.) _Fam._ Tubicolæ, Lam.
Pyloridea, Bl.--_Descr._ The small, equal, equilateral valves are
cemented into, so as to form part of, a large tube; the umbones are
slightly prominent outside. The tube is elongated, rather irregular,
granulated with sandy particles, and terminated at the base by a convex
disc, which is perforated by small pores, elongated into tubes round
the edge, presenting a resemblance to the spout of a watering pot,
whence the name is derived. _Loc._ New Holland, Java, New Zealand, Red
Sea. Fig. 44. Aspergillum Vaginiferum.

ASSIMINEA. Leach. _Fam._ Turbinacea, Lam.--_Descr._ Inclining to oval,
light, thin, covered with a horny epidermis, spire produced into an
acute pyramid; whorls slightly angulated in the centre, rounded
beneath; aperture elliptical, slightly modified by the last whorl;
inner lip planed; outer lip thin; operculum horny, subspiral. Found in
brackish water; one species may be procured abundantly on the muddy
shores of the Thames, in Kent. There are also species from Calcutta,
China, Tahiti, and Australia. Without comparing the animals, it is
difficult to distinguish this genus from some species of Littorina.
Fig. 363. A. Grayana.

ASTACOLUS. Montf. A genus of microscopic Foraminifera. CRISTELLARIA
Crepidula, Lam.

ASTARTE J. Sowerby. (Name of a Sidonian Goddess, _Ashtaroth_ in
Scripture.) _Fam._ Nymphacea, Lam. Genus Crassina, Lam.--_Descr._
Suborbicular, equivalve, inequilateral, thick, compressed; hinge with
two solid diverging teeth in the right valve, one tooth and a slight
posterior elevation in the left; muscular impressions, two in each
valve, uniform, united by a simple palleal impression; ligament
external.--_Obs._ This genus differs from Venus, Cytheræa, &c. in not
having a posterior sinus in the impression of the mantle. The hinge
also differs in having but two cardinal teeth. Astarte differs from
Crassatella in having no internal cartilage in the hinge. Some of the
species are British, others are from America, and one from Sicily. The
fossils occur in Crag, Lower Oolite, &c. Fig. 110. A. Danmoniensis.

ASTROLEPAS. Klein. CORONULA Testudinaria, Auct. CHELONOBIA, Leach. Fig.
15.

ATLANTA. Lesueur. _Fam._ Pteropoda, Lam. and Bl.--_Descr._ Spiral,
convolute, transparent, fragile, compressed, with a broad, fimbriated,
dorsal keel, and a narrow aperture. This shell, which is called "_corne
d'ammon vivant_," is found in the Atlantic. The small Pteropod, figured
in Sowerby's Genera as Limacina, belongs to this genus. Atlanta
Helicialis, fig. 220.

ATRACTODON. Charlesworth. (Mag. Nat. Hist. 2nd series, Vol. 1. p. 218.
) A genus proposed for the admission of a singular fossil shell, found
on the beach at Felix-stone, of which the following are the
characters;--fusiform, aperture equalling the spire in length,
terminating anteriorly in a slightly recurved canal; columellar lip
smooth, curved, thickened posteriorly into a blunt tooth; spire
obtuse.--_Obs._ This shell would be a Fusus were it not for the tooth
on the posterior extremity of the columellar lip. The only species
known is regularly striated in a spiral direction, and named A.
Elegans.

ATRYPA, Dalman. A genus of brachiopodous bivalves, distinguished by the
valves being nearly equal, and the umbones not separated by an
intermediate area. A. reticulata, fig 302.

ATTACHED. Shells are attached to marine substances by various means; in
some cases by a _byssus_, or a bunch of tendinous fibres passing
through an opening between the valves, which gape at their margins to
admit a free passage, as in the genera Byssoarca and Mytilus. In other
cases the byssus is of a more compact substance, and passes through a
perforation in the shell itself. This is the case with many of the
brachiopodous shells, in some species of which the perforation is in
the point of the umbones, a specimen of which is represented in the
Introduction. This species of attachment does not keep the animal
motionless, although it is confined to a particular spot. Other shells
are attached by a portion of their own substance, as in Chama,
Spondylus, Serpula, &c. in which instances, the attached valve is
motionless, and is termed the under valve. The Pedunculated Cirripedes
are attached by a tubular tendinous process, called a peduncle.

ATTENUATED. Drawn out, long, thin, tapering, as the extremities of
Ovulum Volva, fig. 442.

ATYS. Montf. A generic name including those species of BULLA, which are
described as "convolute, with the last whorl covering the rest and
hiding the spire, the apex rounded at both ends." Bulla Naucum, Auct.
fig. 250.

AURICLE. (A little ear.) See AURICULATED.

AURICULA. Lam. (Dim. from _Auris_ an ear.) _Fam._ Auriculacea. Bl.
Colimacea, Lam.--_Descr._ Oval or oblong, cylindrical or conical;
aperture long, narrow, generally narrowest in the centre; rounded
anteriorly, with two or three strong folds on the inner lip, and the
outer lip thickened, reflected or denticulated; spire short, obtuse,
epidermis horny, brown.--_Obs._ The above description includes the A.
coniformis, f. 298. and several other conical species with narrow
apertures which formed the genus _Melampus_, Montf. and _Conovulus_,
Lam. The latter author suppressed his genus on ascertaining the
Conovuli to be land shells. We exclude, however, the A. Dombeyana, Lam.
f. 300. and several similar species, which being more rounded, having
thin outer lips and but one fold on the columella, are described under
the generic name _Chilina_, Gray. It appears rather doubtful whether
the Auriculæ are marine or fluviatile, but the animals appear to be
amphibious. The Auriculæ are principally found in Salt Marshes of
Tropical climates, some small species are found on the Southern
European Coasts, as far north as Britain and south as Tierra del Fuego.
The Auriculæ formed a part of the genus Voluta of Linnæus, f. 297. A.
Judæ, f. 298. A. Coniformis.

AURICULATED. Some bivalve shells, such as _Pecten_, fig. 171, 172, have
a flat, broad, somewhat triangular appendage on one or both sides of
the umbones, called an _auricle_, or little _ear_. If on one side only,
they are said to be _uni-auriculated_; if on both, they are said to be
_bi-auriculated_.

AURICULACEA. Bl. The second family of the order Pulmobranchiata, thus
described; "shell thick, solid; aperture more or less oval, always
large, rounded anteriorly, and contracted by teeth or folds on the
columella." This family is included in the genus Voluta of Linnæus, on
account of the plaited columellar lip, a character by which that
heterogeneous assemblage of shells is distinguished. It forms part of
the family of _Colimacea_, Lam. from which they differ not only in
general form, but also in the fact of the animals being partly
amphibious, always living (according to De Blainville) on the sea
shore, and being occasionally covered with water for a short time. It
contains the genera Pedipes, Auricula, Pyramidella.

AURIFERA. Bl. OTION, Auct.

AURIFORM. (From _Auris_, an ear; _forma_, shape.) Ex. _Haliotis_, fig.
338.

AURISCALPIUM. Megerle. ANATINA, Lam.

AVICULA. Lam. (From _Avis_, a bird). _Fam._ Malleacea, Lam.
Margaritacea, Bl.--_Descr._ Inequivalve, inequilateral, foliaceous,
subquadrate, oblique, pearly; hinge rectilinear, lengthened into
auricular appendages, with a small indistinct tooth in each valve, an
elongated, marginal, ligamentiferous area, and an hiatus in the left
valve, for the passage of a byssus; one circular muscular impression,
near the centre of each valve, with a series of smaller ones arranged
in a line towards the umbones.--_Obs._ The Meleagrinæ of Lamarck,
Margaritiferæ, Schum. included in this description, consist of the more
rounded species, and do not present the elegant obliquity of form, nor
the wing-like auricles from which the genus Avicula receives its name.
The Aviculæ are pearly within. From A. margaritifera, a young specimen
of which is figured in the plates, fig. 164, is obtained oriental
pearls. This is an example of Meleagrina. A. Hirundo, fig. 163, belongs
to the genus Avicula of Lamarck. It is, however, needless to continue
the separation. Aviculæ are from E. and W. Indies, Mexico, Coasts of
the Pacific, Mediterranean, British Islands, &c. Fossil species occur
in the London clay, &c.

AXINUS. J. Sowerby.--_Descr._ Equivalve, transverse; posterior side
very short, rounded, with a long ligament, placed in a furrow,
extending along the whole edge; anterior side produced, angulated,
truncated, with a flattish _lunule_ near the beaks. The late Mr. James
Sowerby, who described this shell in the Mineral Conchology, did not
consider his genus as established, not having seen the hinge.

AXIS. The imaginary line, round which the whorls of a spiral shell
revolve. The extremities of the axis are pointed out in fig. 379, by
the letters, _a. a._ See "COLUMELLA."

AZECA. Leach. _Fam._ Colimacea, Lam.--_Descr._ "Animal like Bulinus,
with subcylindrical, rather obtuse shell, covered with a polished
periostraca (epidermis); aperture pear-shaped, curved and pointed at
the top; the margin thick, obtuse, united all round and toothed; the
axis imperforated." Gray's edition of Turton's British Shells, page
189.--_Obs._ The Turbo Tridens of Montagu, upon which this genus is
founded, resembles Bulinus lubricus in general form and character. Both
these shells differ from the true Bulini in having the peritreme
entire, and in being pellucid and glossy. Azeca differs from Bulinus
lubricus in having three teeth in the aperture, two on the inner lip
and one on the outer. Not seeing the necessity for creating a genus on
grounds so slight, I have simply transcribed the description given
above, leaving others to form their own conclusions as to the propriety
of separating this shell from the genus Bulinus. Britain, Central and
Southern Europe. Azeca Tridens, fig. 290.

AZEMUS. Ranzani. CONIA, Leach.

BACULITES. Lam. _Fam._ Orthocerata, Bl. Ammonacea, Lam.--_Descr._
Straight, conical, tubular, laterally compressed; chambers divided by
very sinuous lobed septa, the last elongated; aperture elliptical;
siphon dorsal.--_Obs._ This genus differs from Orthoceras in the same
manner in which Ammonites differs from Nautilus, having its septa
sinuated and branched. A Baculite might be described as a straight
Ammonite. This genus is known only in a fossil state. It is found in
the Cretaceous Limestone of Maëstricht and Valognes. Fig. 484. B.
Faujasii.

BALANUS. Brug. (an Acorn; "gland de Mer." Fr.) _Order_ Sessile
Cirripedes, Lam. _Fam._ Balanidea, Bl.--_Descr._ Shell composed of six
valves articulated to each other side by side in a circle, by the
insertion of lamina; closed at the base by a flat, cylindrical or
cup-shaped valve, by which it is generally attached; and at the apex by
a conical operculum, consisting of four valves in anterior and
posterior pairs. Each valve of the shell is divided into a rough
triangular portion pointed towards the apex, and a flat area on each
side.--_Obs._ This description includes the _Acasta_ of Leach, which
growing in sponges, has the base cup-shaped; _Conoplæa_ of Say, which
being attached to the stems of Gorgonia and sea-weeds has the base
elongated and lanceolate, and _Chirona_, Gray. Balanus is the only
genus of Sessile Cirripedes the shells of which consist of six parietal
valves, except _coronula_, which has no shelly base, is flatter, and
has the valves of the operculum placed horizontally. The Balani are
common in all seas, adhering to rocks, corals, floating timber, and to
each other. The fossil species are found in the newest strata, at
Bordeaux, Paris, &c. Fig. 25. B. Tintinnabulum; 26. _Acasta_ Montagui;
27. Balanus galeatus, _Conoplæa_, Say.

BALANIDEA. Bl. The second family of the class Nematopoda, Bl.
corresponding with Sessile Cirripedes, Lam., and consisting of
Coronular Multivalves, which are fixed, and in a manner soldered to
submarine substances, by the base of the shell; as distinguished from
the Lepadicea, Bl., Pedunculated Cirripedes, Lam., which are attached
by a fleshy stalk. The Balanidea are composed of two sets of valves,
besides the shelly plate or base on which they rest. The first, called
the Parietal valves, are arranged so as to surround the body of the
animal; the second, called the Opercular valves, are placed
horizontally, so as to cover the aperture.

BALEA. Gray. _Fam._ Colimacea, Lam.--_Descr._ Spiral, turrited,
concentrically striated, sinistral, and covered with a thin brown
epidermis; spire composed of numerous whorls, gradually increasing in
size; aperture small, sub-quadrate; peritrême entire, slightly
thickened, with a very slight fold on the columella; axis
perforated.--_Obs._ A genus of small land shells, found in moss at the
roots of trees in Britain, not very nearly resembling any other land
shells, except Clausilia, from which they differ in not having the
clausium. They have been placed in Helix by De Ferrusac, and in Pupa by
Draparnaud. B. fragilis, fig. 296. _Helix perversa_, Fer. _Pupa
perversa_, Drap.

BARBATA. Humphrey. UNIO, Lam.

BARNACLES. PENTELASMIS, Auct. (fig. 34.) Called Anatifa, by Linnæus and
Lamarck, from the ancient notion that they were the eggs or embryo of
the Barnacle Duck. See ANATIFER.

BASE. In all shells which are attached to sub-marine substances, the
base is that part of the shell which forms the point of attachment,--as
for instance, the attached valve of Spondylus, the basal plate of
Balanus, the lower part of the peduncle of Pentelasmis; in Unattached
Bivalves, the margin opposite to the umbones, where the foot of the
animal, or the part analogous to it, protrudes; in spiral univalves,
the aperture, which rests on the back of the animal when walking.
Lamarck and some other authors have used the term _base_ as simply
opposed to apex, and apply it to the anterior of the aperture.

BATOLITES. Montf. HIPPURITES, Auct.

BEAK. The Apices, or points of the valves of a bivalve shell, generally
termed UMBONES, in descriptions. Also any part which is rostrated or
drawn out like a beak.

BEAKED. See BEAK and ROSTRATED.

BEAR'S-PAW-CLAM. The common name for Hippopus maculatus, a
representation of which is given in the plates, fig. 156.

BELEMNITES. Auct. ([Greek: Belemnon], _belemnon_, a dart, or arrow.)
_Fam._ Orthocerata, Bl. and Lam.--_Descr._ Straight, conical,
consisting of two parts; the _external_ portion forming a thick solid
sheath, with a cavity at the base to admit the internal portion or
nucleus, which is mathematically conical, and is divided into chambers
by smooth simple septa perforated by a lateral siphon.--_Obs._ These
singular fossils, which are found in most secondary beds, have long
attracted the attention of philosophers as well as of the ignorant,
from whom they have received the various appellations of
Thunder-Stones, Petrified Arrows, Petrified Fingers, Devil's Fingers,
Spectre Candles, &c. The above description is framed to include the
genera Hibolithes, Porodragus, Cetocis, Acamas, and Paclites of De
Montfort, and Actinocamax, Stokes. Fig. 466 to 468.

BELLEROPHON. Montf. (or Bellerophus).--_Descr._ Convolute, symmetrical,
umbilicated, with a double dorsal ridge; aperture wide,
semilunar.--_Obs._ The fossils composing this genus resemble Nautilus
in general appearance, but not being chambered shells they approach
very near to Argonauta, from which they differ only in the thickness of
their shell and in roundness of their external form. This genus is
erroneously placed by De Montfort among chambered shells, and by De
Blainville next to Bulla. It belongs to the Monothalamous Cephalopoda
of Lamarck. This fossil is found principally in the Carboniferous
Limestone. Fig. 486, 487, represent B. tenuifasciata.

BELOPTERA. The bony support of a species of Cuttlefish, partly
resembling Sepia.

BIAPHOLIUS. Leach. A genus believed to be identical with Hiatella.

BI-AURICULATED. Having two auricles placed at the sides of the umbones,
as in Pecten, fig. 171. See AURICULATED.

BICATILLUS. Sw. A sub-genus of "Calyptrædæ," including those species,
which have cup-shaped internal septa, as for example, Calyptræa
extinctorium, fig. 235.

BICONIA. Sw. A sub-genus of "Calyptrædæ," including those species in
which the septum is partly spiral.

BIFID. Divided, double.

BIFRONTIA. Deshayes. Also OMALAXIS, Desh. _Fam._ Turbinacea,
Lam.--_Descr._ Discoidal, planorbicular, with whorls sometimes not
contiguous; umbilicus deep, keeled at the margin; aperture
subtriangular, somewhat dilated; outer lip acute, separated by a deep
notch at both extremities.--_Obs._ We do not see any reason for
separating this genus from SOLARIUM, except the last mentioned
character. The few fossil species which this genus contains (Solarium
disjunctum, Bifrons, &c.) are found principally in the Paris basin.
Fig. 354. Solarium Bifrons.

BI-FURCATE. Double pronged, or having two points. _Ex._ the internal
appendage of Calyptræa Equestris, fig. 234.

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

BILABIATED. Having the edge of the outer lip as it were doubled, by one
part of the lip being more thickened and reflected than the other, so
as to form a ledge, or second lip.

BILOBATE. Having two prominent parts, as the outer lip of Rostellaria
Pes-Peleeani, fig. 404.

BIPARTITE. Composed of or divided into two parts; double; as the valves
of Platylepas, fig. 19, each of which has a septiform division in the
centre; also the area on the hinge of Spondylus. See Frontispiece.

BIROSTRA. Sw. A genus composed of species of OVULUM, which have
elongated extremities, as, for instance, Ovulum Volva, fig. 442.

BIROSTRITES. Lam. (Double Beak.) A fossil formerly considered as a
distinct bivalve shell, with conical umbones, and placed in the family
of Rudistes by Lamarck, but now known to be an internal cast of
Sphærulites, fig. 196.

BISIPHYTES. Described by De Montfort as resembling a Nautilus, but
having two distinct siphons. As no such fossil species is now known to
Naturalists, it appears probable that De Montfort having a specimen of
some Nautilus, with an accidental depression, took it for a second
siphon.

BITHINIA. Gray. A genus described as differing from PALUDINA, in having
the operculum shelly, and the mouth of the shell thickened internally.
PALUDINA impura, Auct. Fig. 537.

BITOMUS. Montf. A microscopic shell, deriving this general appellation,
from the appearance of a double aperture.

BIVALVE. A shell composed of two equal, or nearly equal principal
parts, each part having a separate nucleus, turning upon each other by
means of a hinge. The class Conchifera of Lamarck, Acephalophora of De
Blainville severally include the whole of the bivalve shells; the
latter name being derived from the fact that the animals have not
distinct heads, and neither eyes nor tentacula. All bivalve shells are
marine or fresh-water. They form the class Dithyra of Aristotle. It may
be observed that some of the Acephalophora, the Pholades, for example,
have small testaceous pieces fixed on the hinge, which are called
accessary valves. These are still fairly bivalve shells, although the
genus Pholas has been placed by some writers among the multivalves.

BOAR'S TUSK. A common name given to shells of the genus Dentalium. One
particular species has received a specific name in accordance with a
supposed resemblance, namely, Dentalium Aprinum, (of a Boar.)

BONELLIA. Desh. A genus formed, in the first instance, for the
reception of Bulinus terebellatus, Lam. which Mr. G. B. Sowerby, in his
Genera of Shells, united with the genus PYRAMIDELLA. M. Deshayes,
however, in his new edition of Lamarck, makes the genus Bonellia
include several species which I have arranged in the genus Eulima. From
the remarks of M. Deshayes, tom. 8, p. 286, 287, we are led to suppose
that the estimated difference between Eulima and Bonellia consists in
the latter having the axis perforated; or in other words, umbilicated.
After remarking "que Mr. Sowerby, junr. confond deux choses bien
distinctes, sous le nomme d'Eulima," M. Deshayes gives the following
description of his genus, (translated) "shell turriculated, smooth,
polished, with the apex acute and laterally inclined; axis perforated
throughout its length; aperture small, entire, angular at the
extremities; columella simple and without folds; outer lip thin,
simple, nearly parallel with the longitudinal axis." That author
further remarks, "Mr. Sowerby, junr. à signalé cinque espèces vivant,
que nous rapportons à notre genre." (Sowerby, junr. Conchological
Illustrations, parts 52 and 53; 50, Great Russell Street, Bloomsbury.)
The species thus selected are E. splendidula, E. marmorata, E.
interrupta, E. imbricata, E. brunnea; the two last of which have the
umbilicus so inconsiderable, as to be scarcely distinguishable from
other species, which M. Deshayes has left in the genus Eulima, and
which have a slight hollow, almost approaching to a perforation, behind
the columella. Eulima marmorata, (Bonellia, Desh.) is figured in the
plates, fig. 348.

BODY WHORL. The last whorl, constituting the bulk of the shell.

BORELIS. Montf. MELONIA, Bl. A genus of microscopic Foraminifera.

BORER or PIERCER. A term applied to those species of Acephalopodous
Mollusca, which bore holes as dwellings in the rocks, as the Pholades,
and some others.

BRACHIOPODA. Lam. A family of symmetrical bivalves belonging to the
third section of Lamarck's _order_ "Conchifera Monomyaria," described
as bivalve (generally symmetrical) adhering to marine bodies, by a
tendon passing through the shell, having no true ligament. What most
distinguishes this family and renders it remarkable is the structure of
the animal. It has two elongated, tendril-shaped arms. When the animal
is in a state of repose these arms are coiled up spirally and enclosed
in the shell, but when required for use, are unfolded and extended.
This family contains the genera Orbicula, Terebratula and Lingula, in
the system of Lamarck, to which may be added Thecidium, Productus,
Spirifer, Magas, Pentamerus, Crania, Strigocephalus, Strophomena, and
some others enumerated in the explanation of figures 201 to 219. The
above genera may be thus distinguished.

1. ORBICULA. Umbones central; byssus passing through a hole in the
flat valve. Fig. 201.

2. ATRYPA. Without foramen or space between the valves. Fig. 203.

3. PRODUCTA. The same, valves produced, overwrapping; including
Leptæna. Fig. 206, 206*.

4. TEREBRATULA. Hinge of the upper valve produced beyond that of
the other, with a pit or foramen; including _Delthyris_, _Orthis_,
_Trigonosemus_, _Magas_, _Strophomena_. Fig. 202, 205, 207, 208,
209.

5. SPIRIFER. The same, with deep triangular area; spiral folds in
the interior; including _Trigonotreta_ and _Cyrtia_. Fig. 204, 214,
215.

6. THECIDIUM. Large valve attached; curved ridges in the inner
surface; two jutting points or teeth on the hinge. Fig. 216.

7. CRANIA. Attached by the surface of the valve; muscular
impressions four, forming a face. Fig. 197, _a_, b.

8. PYCNODONTA. Irregular; hinge with raised pointed teeth. Fig.
217, 218.

9. PENTAMERUS. Valves divided by septa; including _Gypidia_. Fig.
210 to 213.

10. LINGULA. Valves equal, gaping, with a peduncle. Fig. 219.

BRACHITOMA. Swainson. A genus composed of PLEUROTOMA strombiformis and
similar species, described as "sub-fusiform; resembling a small
Strombus or Fusus; spire and aperture of equal length; canal short;
outer lip slightly ascending, and forming a short canal; sinus very
small and nearly semicircular; inner lip thickened above. B.
Strombiformis, Sow. Man. fig. 381." Europe, East and West Indies,
China, &c.

BRANCHIFERA. Bl. The second family of the order Cervicobranchiata,
containing the following genera of symmetrical univalves:--Fissurella,
Emarginula, and Parmophorus.

BRISMÆUS. Leach. _Order._ Pedunculated Cirripedes. Lam.--_Descr._ Seven
plates, three pairs lateral, one dorsal; form cylindrically conical;
pedicle not described. _Hab._ Holes in corals. B. Rhophodius, fig.
38.--_Obs._ This minute shell most nearly resembles Pollicipes
Mitellus, fig. 37*, but the difference may be seen at once by comparing
the figures.

BRONTES. Montf. This generic name is given to such species of MUREX as
have a very long, closed canal; with a short spire, circular aperture,
and are destitute of spires and ramifications. Brontes (Murex)
Haustellum, fig. 390.

BUCARDIA. Schum. ISOCARDIA, Auct.

BUCCINUM. Linn. _Fam._ Purpurifera, Lam. Entomostomata, Bl.--_Descr._
Subovate or oblong, covered with an epidermis; spire turrited,
consisting of few whorls; aperture wide, subovate, terminating
anteriorly in a very short canal, reflected over the back; outer lip
simple, slightly reflected; inner lip spread over a portion of the body
whorl, terminating in a thick, smooth columella; operculum horny.
_Hab._ British Seas, Northern Ocean, and Coast of Africa. Most of the
fossil species occur in Crag, some in upper marine formation and London
clay.--_Obs._ There are considerable difficulties in keeping this genus
distinct from others nearly related to it, into which many of the
species run by imperceptible gradations. The genus _Nassa_ has been
separated on account of the little notch, which terminates the
columella. Some species of Terebra come so close upon the Buccina, that
it is difficult to say where one genus ends and the other begins. T.
Buccinoides, fig. 427. Buccinum Undatum, the common Whelk, fig. 421.

BUFO. Montf. A generic division of the species composing Ranella,
characterized as having the shell not umbilicated. _Ex._ R. ranina,
fig. 394. The above character is scarcely sufficient in some cases,
even as a specific distinction.

BULBUS. Humph. RAPELLA, Swainson. A genus formed for the reception of
PYRULA papyracea, Auct. (fig. 389), and similar species. RAPANUS,
Montf.

BULIMIMA. Montf. A genus of microscopic Foraminifera.

BULIMULUS. Leach. _Fam._ Colimacea, Lam. The author is unacquainted
with the characters by which the two or three species included in this
genus are to be distinguished from Bulinus. We have represented, fig.
283, Bulimulus trifasciatus, Leach, (Bulinus Guadaloupensis, Auct.)
This occurs in the same limestone which encloses the half fossilized
human remains from the Grand Terre of Guadaloup. Several species are
described by the Rev. L. Guilding in the Zoological Journal, namely,
the B. Undulatus, Antiguensis, and Proteus; but neither from the shells
themselves, nor from the figures of the animal, can we draw any
information as to the generic character; the difference alleged by Mr.
Swainson and Mr. Gray being a comparative thinness in the outer lip.

BULINUS. Brug. (Bulinus, Lam.) _Fam._ Colimacea, Lam. Limacinea,
Bl.--_Descr._ Oval or oblong, light, covered with a thin epidermis;
spire obtuse, variable in length and in the number of whorls, which are
generally few; aperture wide, oval, rounded anteriorly; outer lip
simple, usually reflected, joining the columella without a sinus; inner
lip reflected over part of the body-whorl. The Bulini are land shells,
found in many parts of the world.--_Obs._ The genus Bulinus can only be
distinguished from Helix by its oval form; it forms part of the genus
Helix of De Ferrusac, under the sub-generic designation of Cochlostyla.
It is known from Achatina by the absence of the notch at the point of
union between the inner and the outer lips. The young are produced from
eggs, which are as firm and opaque as those of birds. (See
Introduction.) Bulinus rosaceus, fig. 282. B. Guadaloupensis, fig. 283.
B. Lionetianus, fig. 284. B. lubricus, fig. 285. Many new species were
brought to this country by Mr. Cuming, and are represented in the
Conchological Illustrations, published by the Author at 50, Great
Russell Street, Bloomsbury, (in parts 21, 22, 23, 26, 27, 30, 31, 34,
35, 137 to 146, 185, 186.) Species occur in Europe, West Indies,
Brazil, and South America generally. Some small species are British.

BULLA. Auct. _Fam._ "Bulléens," Lam. Akera, Bl.--_Descr._ Generally
thin, smooth, oval, oblong or cylindrical, more or less convolute;
spire short, depressed, or hidden by the last whorl; aperture long,
wide in front, gradually narrowing towards the spire; outer lip thin;
inner lip spread over a part of the last whorl.--_Obs._ The shells
composing this genus are very variable in form. The light horny species
with an elastic lip is called Akera, fig. 247. The more decidedly
convolute species with hidden spires are the Atys, Montf. B. Naucum,
fig. 250. B. Lignaria, fig. 251, is Scaphander of Leach. The light,
thin species, with extremely wide aperture, fig. 248, is Bullæa aperta,
Lam. The genus Bullinula of Dr. Beck, consists of those species which
have more produced spines, fig. 253. The Bullæ are marine, and inhabit
all climates. The fossil species occur in tertiary beds.

BULLÆA. Lam. BULLA aperta, Auct. fig. 248.

BULLÆANA. ("Bulléens, Lam.") A family belonging to the first section of
Lamarck's order, Gasteropoda, containing the genus Bulla. The genera
Bullæa, Akera, Aplustra, Atys, Scaphander, Bullinula, into which it has
been divided, may all be fairly included under the name BULLA.

BULLIA. Gray. A genus of shells partly resembling Buccinum, and Terebra
in general form, being more elongated than the former and more
ventricose than the latter. Mr. Gray remarks in the Synopsis of the
British Museum, page 114, that the Bulliæ resemble the Nassæ in most
characters, "but they have a very large, broad foot, and the hinder
part of the inner lip of the shell being extended beyond the mouth,
forms a raised enamelled band round the suture of the whorls, as is
also the case with the Ancillariæ and some Volutes." Bullia vittata,
fig. 427, is an example of the genus. The name Subula is given by De
Blainville to the other species of Terebra, so that if both these
genera were admitted, the old genus Terebra must be expunged.

BULLINULA. Beck. Species of BULLA, with produced conical spires, fig.
253.

BYSSOARCA. Sw. (_Byssus_ and _Arca_.) _Fam._ Arcacea, Lam. A genus of
bivalve shells, composed of the Arca _Noæ_, and several other species,
separated from the genus Arca on account of their shells being attached
by means of a byssus passing through an hiatus in the ventral margins.
B. _Noæ_, fig. 132. The species occur in Southern Europe, East and West
Indies, China; also, on the coasts of Great Britain.

BYSSOMYA. Cuvier. (_Byssus_ and _Mya_.) De Blainville states that
although the shell of this proposed genus resembles Saxicava, the
animal is sufficiently different to justify the separation.

BYSSUS. ([Greek: Bussos], _byssus_, ancient name for linen.) The
tendinous fibres by which some Bivalves are as it were anchored or
moored to sub-marine substances. A fine example of this is to be seen
in the Pinnæ which bear some resemblance to large Muscle Shells and
have an hiatus in the margins of the valves through which a bunch of
silken fibres passes. In the British Museum there is preserved a pair
of gloves which have been woven of these fibres. The Byssus is peculiar
to some bivalve shells such as Muscles, Hammer Oysters, Arca Noæ, &c.

CALCAR. Montf. (a spur.) A genus composed of TROCHUS STELLARIS, Lam.
and other depressed species of Trochus which are characterized by a
stellated keel round the angle of the last whorl; but not including T.
Imperialis, which is the genus Imperator, Montf. The difference
consists in the latter being umbilicated and the former not. T.
stellaris, fig. 358.

CALCAREOUS, (_calx_, lime.) A term applied to a shell or to its
operculum which is composed principally of lime or shelly matter, as is
usually the case, in distinction from one which is of an horny,
membranaceous texture. The greater number of shells are calcareous, but
it forms an important point of distinction with regard to the
operculum. The only difference between the genera Trochus and Turbo, as
at present established, depends upon the calcareous or shelly, and the
corneus or horny texture of the operculum.

CALCEOLA. _Fam._ Rudistes, Lam. and Bl.--_Descr._ Equilateral,
inequivalve, triangular; umbones separated by a large triangular disc
in the lower valve; cardinal margin straight, linear, dentated; lower
valve large, deep; upper valve flat, semi-orbicular, forming a kind of
operculum to the lower.--_Obs._ This singular shell, known only in a
fossil state, in the Palæozöic beds, is placed by Linnæus in the genus
Anomia. Lamarck places it among his Rudistes, but Mr. Sowerby in his
genera of Shells, states that it should be added to the family of
Brachiopoda. Fig. 194, 195. C. Sandalina.

CALLANTICA. Gray. POLLICIPES hispidus, Leach.

CALLIA. Gray? A genus described as having a peculiarly polished shell
like Pupina, but wanting the notch.

CALLISOSTOMA. Sw. A genus of shells separated from TROCHUS, and thus
described, "Imperforate; spire elevated, acute; aperture broader than
high, transversely ovate, hardly sinuated at the base, and slightly
oblique; shells always smooth, and often polished." C. zizyphina is
mentioned as an example.

CALLIRHOE. Montf. p. 362, vol. 2. Appears to be figured from the nut or
inner portion of a large Belemnite.

CALLISCAPHA. Gray? IRIDINA Nilotica, Sow. Zool. Journ. 1. pl. 2.
Separated from Iridina on account of the hinge margin being smooth.

CALLITHEA. Sw. A sub-genus of Mitræ, consisting of those species, which
like M. sanguisuga, have the "spire and aperture of nearly equal
length; internal channel nearly obsolete; shell with longitudinal
linear ribs, crossed by transverse striæ and bands; base contracted."
Swainson Mallac. Lard. Cyclop.

CALLOSITY. A term used in general zoology to express those hard horny
tumidities formed in the skin of some animals, (such as the Dromedary,
for instance) in those parts which are most frequently used. It is not
used in this sense by Conchologists, who apply it to those undefined
tumidities or bumps which appear on the inner surface and hinge of some
bivalve shells, and to the thickening over the umbilicus of Naticæ.
Glycimeris, fig. 67. Natica, fig. 327, 328.

CALPURNUS. Montf. OVULUM _verrucosum_, Auct. Distinguished by the small
circular tubercle at the back of each extremity of the shell. Fig. 441.

CALYPTRACEA. Lam. A family belonging to the first section of the order
Gasteropoda, Lam., the shells of which are described as always
external, covering the animal, and having no operculum. The genera
contained in this family may be thus distinguished.

1. CALYPTRÆA. Conical; apex central, septum spiral, cup-shaped, or
forked; including _Infundibulum_. Fig. 234 to 238.

2. CREPIDULA. Apex terminal; septum flat, reaching half across the
aperture. Fig. 239.

3. CAPULUS. Conical; apex obliquely curved, no septum. Fig. 240.

4. EMARGINULA. Apex curved backwards; a notch in the anterior
margin; including _Parmophorus_. Fig. 241, 242.

5. CEMORIA. A slit _near_ the apex. Fig. 244.

6. FISSURELLA. A slit _upon_ the apex. Fig. 245.

7. RIMULA. A slit near the margin. Fig. 243.

8. ANCYLUS. Apex curved sidewise. Fig. 246.

CALYPTRACEA. Bl. The second family of the order Scutibranchiata. Bl.
thus described: "Shell more or less conical, not spiral, or very
slightly so; aperture large and entire." The genera included in this
family are Crepidula, Calyptræa, Capulus, Hipponyx, and Notrêma.

CALYPTRÆA. Lam. _Fam._ Calyptracea, Lam. and Bl.--_Descr._ Conical,
patelliform, irregular, with an internal, lateral, salient plate or
septum, varying in form.--_Obs._ The internal appendage is in some
species cup-shaped, in some it juts out of the centre in a double
point; in others it is only a small flap; and in others a spiral disc.
These last, which are shaped like Trochus, are separated by De Montfort
under the appellation INFUNDIBULUM; TROCHATELLA, Sw. The Calyptræa may
be known from Crepidula by the septum, which in the latter is a flat
plate reaching half way across the cavity. Fig. 234, 5, 6.

CAMERINA. Brug. NUMMULITES, Auct.

CAMILLUS. Montf. A genus founded upon a minute spiral shell, with a
triangular aperture, turned over the back of the last whorl. It is
figured in Soldani's Testacea Microscopica.

CAMPULOTUS. Guettard. MAGILUS, Auct.

CANAL. A groove which characterizes some spiral univalves, where the
inner and outer lips unite at the front part of the aperture. This
canal is drawn out in some shells to a considerable length, in others
it is turned abruptly over the back. The family Canaliferæ, Lam. (fig.
372 to 401), are all provided with this canal.

CANALICULATED. Applied generally to any distinct groove or canal.

CANALIFERA. (_Canalifères_, Lam.) A family belonging to the order
Trachelipoda, Lam. nearly corresponding with the family Entomostomata
in De Blainville's system, and described as having a canal of greater
or less extent at the anterior part of the aperture. This canal is
sometimes straight, sometimes tortuous, and in some genera it is
recurved over the back of the shell. All the shells have an operculum,
and the thickness of the perfectly formed outer lip does not increase
with age. The Canalifera are characterized by having a canal, in
distinction from the Purpurifera, which have only a notch. This family
contains the following genera,

1. CERITHIUM. Club-shaped. Fig. 372.

2. POTAMIS. The same, fresh water. Fig. 377.

3. NERINEA. The same, with internal folds. Fig. 374.

4. TRIPHORA. Anterior and posterior canals closed so as to present
three openings. Fig. 375, 376.

5. TELESCOPIUM. Pyramidal, trochiform. Fig. 378.

6. PLEUROTOMA. A slit on the upper part of the outer lip; including
_Clavatula_. Fig. 379, 381.

7. TURBINELLA. Three horizontal folds on the columella. Fig. 382,
383.

8. SPIRILLUS. Spire papillary; one fold on the columella. Fig. 384.

9. CANCELLARIA. Three folds, and internal costæ. Fig. 385.

10. FASCIOLARIA. Oblique folds, the lowest the largest. Fig. 386.

11. FUSUS. Fusiform; no folds on the columella. Fig. 387.

12. PYRULA. Pear-shaped. Fig. 388 to 390.

13. STRUTHIOLARIA. Outer lip thickened; sinuated. Fig. 391.

14. RANELLA. Two rows of varices; a canal at each extremity of the
aperture. Fig. 393, 394.

15. MUREX. Three or more rows of varices; only one distinct canal.
Fig. 395, 396.

16. TYPHIS. A tubular perforation between each varix. Fig. 397.

17. TRITON. Varices not in rows. Fig. 398 to 401.

CANCELLARIA. Auct. (From _Cancellatus_, cross-barred, like window
frames or net work.) _Fam._ Canalifera, Lam. Entomostomata, Bl.--Descr.
Oval, thick, cancellated; spire generally short, pointed; aperture
sub-ovate, emarginated anteriorly, pointed at the posterior extremity;
outer lip marked within by transverse ridges; inner lip spread over
part of the body whorl, terminating in a straight, thick, obtuse
columella, with several strong oblique folds. _Hab._ Indian Ocean,
Coast of Africa, America, and West Indies. Fossils found in London Clay
and Calc-grossier of Paris. Differing from Turbinellus in form and in
the transversely ribbed inside of the outer lip. Fig. 315. C.
reticulata.--_Obs._ The latest enumeration of the species of this genus
is contained in a catalogue published by Mr. G. B. Sowerby, senior,
accompanying the author's figures of the new species, amounting to 38,
in parts 9 to 13 of the Conchological Illustrations. The greater part
of these new species were brought to this country by Mr. Cuming.

CANCELLATED. (From _Cancellatus_, cross-barred.) Applied generally to
any shells which are marked by ridges crossing each other as
Cancellaria, fig. 385.

CANCILLA. Sw. A sub-genus of Mitræ, described as having "the whorls
crossed by transverse linear ribs; inner canal wanting, plates very
oblique; form slender; outer lip thin." _Ex._ M. Isabella, M. sulcata.

CANCRIS. Montf. CREPIDULINA, Bl. A genus of microscopic Foraminifera.

CANOPUS. Montf. A genus of microscopic Foraminifera.

CANTHAPLEURA. Guild. A genus composed of those species of Chiton, which
have the mantle rough, with moveable spines, prickles, or hairs. _Ex._
C. spinosus, fig. 227.

CANTHARIDUS. Montf. TROCHUS IRIS, Auct. and analogous species.
Elenchus, Humph.

CANTHARUS. Montf. A genus of microscopic Foraminifera.

CANTHIDOMUS. Sw. A sub-genus of Melanopsis, thus described: "spire
generally short; whorls coronated with spines, or marked with
longitudinal ribs; base obtuse. C. costata, Sow. Gen. f. 3." Melanopsis
costata, plates, fig. 315.