VENERIDiE. MOLLUSOA. Cycladid^, 
larly heart-shaped ventricose shell, with three com- 
pressed, erect teeth in the hinge in each valve. The 
margins of the shell, internally, are finely crenulate, 
and the pallial sinus is short, narrow, triangular. There 
are only four species described, all from the American 
seas. The hinder margin of the inner surface of each 
valve of one species {M. violacea) is of a fine deep violet 
colour ; and, as already mentioned, it is this shell which 
the Red Men in America regard with so much interest 
and use as wampum. 
Genus Chione. — This genus has an ovately triangu- 
lar, somewhat thickened shell, with the margins finely 
crenulated. The hinge is solid and provided with three 
teeth in the right, and two in the left valve. The 
external ligament is narrow, and the pallial sinus is 
nearly obsolete or very short and triangular. The sur- 
face of the shell in this genus, which varies a good deal 
in form, is lamellated, cancellated, smooth, or trans- 
versely striated. 
Genus Tapes. — This genus consists of oblong shells, 
with the hinder end the longest, the margins smooth, 
and the hinge provided with three compressed, slightly 
diverging cardinal teeth in each valve, two of which 
are usually bifid. The pallial sinus is deep and rounded. 
The foot of the animal in this genus occasionally spins 
a byssus, by which it secures itself when it is in danger 
of being carried away. “ The Tapes pullastra, which 
is usually free — for I have often found it so, and never 
moored, if placed in a situation where it would be liable 
to be carried away by the current — averts the fatal wreck 
by attaching itself by some filaments to the shingle or 
stones around it.” — Johnston. 
Genus Venerupis, or the Venus of the Rock . — 
This genus has an oblong shell, gaping a little pos- 
teriorly, and a hinge with three small teeth in each 
valve, one of them being bifid. The pallial sinus is 
moderately deep and angular, and the surface of the 
shell is radiatel}" -striated and ornamented with con- 
centric lamelloe. The species are generally found in 
crevices of rocks, and are said to possess the power of 
perforating the limestone or chalk, &c., in which they 
are lodged. Mr. Rang admits this power, and says that 
when they have reached their adult state they cannot 
get out of the cavities they have made, “ the aperture of 
the excavation being too small to admit of their egress.” 
Mr. Sowerby, however, thinks that the cavities in 
which these shells live “ are rather the natural conse- 
quence of the action of the sea-water in conjunction 
with some of the excretions of the animal upon the 
chalk or limestone, than of any power of the animals 
themselves to pierce independently of such action.” 
Sowerby, however, here confuses the two genera Tapes 
and Venerupis, while Rang strictly confines the genus 
Venerupis to those species which really do bore. 
Several other genera belong to this family ; but as the 
species in each are few, we must pass them over and 
proceed to the next. 
Family— CYPRINID^. 
This family consists of substantial, thick shells, 
invested with a strongly developed epidermis. They 
are ovate-cordate, with prominent incurved beaks, no 
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361 
lunule, and smooth maigins. The hinge is furnished 
with three cardinal teeth, and one lateral tooth in each 
valve. The ligament is external, thick, elongated; 
and the pallial line is simple. 
Genus Cyprina. — This genus is the only one known, 
and there is only one species in the genus. The C. 
islandica is one of the largest of our British shells, and, 
besides, is common to European and North American 
seas. It ranges, indeed, from Greenland and the United 
States to the Icy sea. It is said to be carnivorous in its 
habits, and Dr. Johnston tells us that it often swallows 
the bait of the fishermen. He found in the stomach of 
an individual the indigested remains of a large green 
Nereis. 
Family— GLAUCONOMIDiE. 
This family is by many authors placed amongst the 
Veneridee. 
Genus Glauconome. — This is the only one. In it 
the shell is oblong-oval, thin, and covered with a hard, 
olive-green epidermis extending beyond the edge of the 
valve. The binge is narrow, and furnished with three 
cardinal teeth in each valve, one of which is bifid. The 
ligament is external, marginal, and the pallial sinus is 
very deep and angular’. The species of this genus are 
all natives of the mouths of rivers, even where the 
water is partially fresh. They appear to be exclusively 
confined to the Philippine Islands and Indian seas. They 
live buried in the sandy mud of the estuaries, and 
appear to be very similar in their habits of life to the 
Solens or Razor- fish. 
Family— PETRICOLIDAE. 
The Petricolas have an ovate-elongated, thin, tumid, 
gaping, often irregular shell, which is usually white, or 
covered with a thin, hard epidermis. The hinge is 
narrow, and has two cardinal teeth in each valve, 
which are bent up as if coming from the inner surface 
of the shell under the umbo. The pallial sinus is deep 
and rounded. The species of this family are generallj 
found burrowing in limestone and coral rocks, and 
srones, or in mud; and appear to be most numerous ic 
Western America. 
Family — CYRENID2B (= Corhiculidoe. — Gray). 
The Cyrenas have a rather tumid, suborbicular shell 
coverel with a hard, brittle, often polished epidermis, 
and a hinge composed of two or three, sometime? 
diverging, cardinal teeth in each valve, and two com- 
pressed lateral teeth, which in some cases are trans- 
versely striated. The shell is solid, the beaks ofter 
eroded, and the surface of the valves is concentrically 
furrowed or striated. The pallial line is only slightly 
sinuated. This family consists of fresh-water shells 
and is numerous in species. The genera are Corhicula 
Batissa, and Cyrena. 
Family— CYCLADID2E. 
The Cy'clases have been separated from the Cyrenida 
because the animals slightly differ. The shell is thin- 
