CHAMIDiE.- 
MOLLUSCA. Cardiid^. 
364 
ciliated fringe of the upper orifice of the mantle moved 
slowly, as if in search of animalcula. Having remained 
in this position about ten minutes, water was ejected 
with considerable force from the lower orifice, which 
till now had remained motionless. The expulsion of 
the water appeared to be effected by a sudden contrac- 
tion of the muscles, because this was never done without 
the valves nearly closing at the same time. After a few 
seconds the valves gradually returned to their open 
position, and remained quiescent as before, till the water 
was again ejected with a jerk. The Heart Cockle 
burrows in sand, forcing its way by means of its sharp 
pointed, triangular foot, leaving only the siphonal 
openings exposed. Only five species are known, one of 
which is an inhabitant of the British seas and the 
Mediterranean, and the others are natives of China 
and the Philippine islands. 
Family— CHAMIDH3, 
The Charaas have an inequivalve, irregular shell, 
adhering to other substances, as rocks, shells, and corals, 
by the outer surface of one of the valves, usually the 
left one. The beaks are recurved, unequal, and the 
hinge is composed of two teeth in one valve, and a 
single large tooth in the other. The valves externally 
are generally foliaceous, and vary very much in form 
and colour. Their shape is usually determined by the 
body to whicb they are fixed. The species are almost 
all from tropical seas, and they especially affect coral 
reefs. The genus is represented in Plate 10, fig. 4, by 
Chama lazarus. 
Family — AN ATINIDH5. 
The Lantern-shells have usually a thin,brittle, oblong, 
often inequivalve shell, gaping at the hinder extremity, 
with a nacreous interior, and generally a granular or 
spinulose exterior. The hinge is obscurely toothed, the 
cardinal teeth being rudimentary ; the ligament is ex- 
ternal, thin, and the cartilage is internal, placed in a 
pit in each valve, and furnished with a peculiar shelly 
hinge-piece or ossicle, which is placed before it, or 
sometimes so as to cover the whole of its surface. 
The family contains several genera. 
Genus Anatina or Laternula. — This genus, the 
Lantern-shell, has a ventricose, thin and translucent 
shell, of an oblong form, gaping and attenuated at 
the hinder extremity. The beaks, which are directed 
backwards, are fissured or slit externally, and are sup- 
ported internally by an oblique plate. The cartilage 
pit in this genus is placed on a projecting spoon-shaped 
process, which is furnished in front with a transverse, 
linear ossicle. The external surface of the valves is 
hispid, or roughened with calcareous points. 
Genus Thracia. — This genus has the cartilage 
placed on a thick, not prominent, callous process on 
the hinge margin, and has a crescentic ossicle. Some 
of the species are found in crevices of rocks, and in the 
burrows of Saxicava, and have in consequence been 
sometimes mistaken for boring shells. 
Genus Chamostrea. — This genus has a shell 
varying considerably in form and appearance from 
the typical species of Anatinidce, but has the internal 
cartilage and ossicle peculiar to the family. The shell 
is inequivalve, like that of the Chama, solid, and attached 
by the anterior side of the deep and strongly-keeled 
right valve. The left valve is flat, and has a conical 
tooth in front of the cartilage, which is furnished with 
an oblong, curved ossicle, not unlike the human clavicle. 
As yet only one species is known ; it is a native of the 
seas of Australia. 
Famii.y— MUTELIDjE (= Iridinidce). 
Notwithstanding the fluviatile habitat, and f/wio-like 
general appearance of the shells of this family, they 
come into this sub-order, as we find the animal having 
the mantle lobes united and produced into two separate 
siphons. The shells are solid, oblong, equivalve, pearly 
w'ithin, and externally covered with a hard polished 
epidermis. The hinge is large, linear, and either 
toothed or toothless. The species of this family are all 
natives of fresh water, and are found either in Africa or 
South America. 
Genus Mutela {=Iridinn ). — This genus has an in- 
equilateral, transverse shell, with the hinge margin 
smooth, without teeth, and attenuated towards the 
beaks, which are small, recurved, and nearly straight. 
The species of Mutela are natives of the livers of 
Africa. One is found in the Nile {M. exotica), and 
the valves are used by the natives of Egypt as spoons 
in measuring oil, butter, and different kinds of pro- 
visions. 
Genus Pleiodon. — This genus (represented in 
Plate 10, fig. 5, by Pleiodon ovaturn), has an ovate, 
strong, and convex shell, with the hinge margin slightly 
arched, which, becoming broader at its extremities, is 
furnished with a series of large, irregular teeth, or 
tubercular crenations. The outer surface of the valves 
is covered with a dark, olive epidermis, and the interior 
is brilliantly lighted up with an iridescent silvery nacre 
generally tinged with pink. The two or three known 
species are all from Africa. 
The other genera are Leila, Castalia, and Hyuia, 
the species of which are all natives of the fresh waters 
of South America. 
Fa m ily — C AEDI IDHH . 
The Cockles have a regular, equivalve, usually in- 
flated, and more or less heart-shaped shell, generally 
ornamented with radiating ribs and furrows. The 
margins interiorly are crenulated ; the ligament is ex- 
ternal, short, and prominent, and the hinge is composed 
of two oblique cardinal teeth, and two elongate, lamellar 
laterals in each valve. The pallial line is simple, or 
slightly sinuated behind. The animals have the foot 
angularly bent behind, enabling them to make leaps, 
prodigious in proportion to their size — the Cardium 
norvegicum being said to be able to effect such jumps 
as to spring out of the vessel in which it is held in 
captivity. The species of this family are very numer- 
ous, upwards of two hundred having been described; 
and are distributed over the whole world, from north 
to south, from east to west, and range from the sea- 
