ORDER TESTACEA. Ill 
A large smooth red species, (the Chama cor. L., Chemn. 
VII. xlviii. 483), inhabits the Mediterranean. 
In the fourth family of the testaceous acephala, the 
CARDIACEA, 
The mantle is open before, and there are besides two separate 
apertures, one for respiration, and the other for the feces, 
which are prolonged in tubes, sometimes distinct, and at 
others united in one single mass. ‘There is always a trans- 
verse muscle at each extremity, and a foot generally used for 
crawling. It may be considered as a general rule, that those 
which are furnished with long tubes live in ooze or in sand. 
This mode of organization may be recognized on the shell, by 
the more or less depressed contour described by the insertion of 
the edges of the mantle, previously to its uniting with the im- 
pression of the posterior transverse muscle. 
CARDIUM, Lin. 
The cardia, like many other bivalves, have an equivalve 
convex shell, with salient summits curved towards the hinge, 
which, when viewing it sideways, give it the figure of a heart : 
hence its name of cardium, heart, &c. Ribs, more or less 
elevated, are regularly distributed from the summits to the 
edges of the valves; but what chiefly distinguishes the cardia 
is the hinge, where we see, on one side and the other, towards 
the centre, two small teeth, and at some distance, anteriorly 
and posteriorly, another tooth, or projecting lamina. ‘The 
animal (CERASTES, Poli) has generally an ample aperture in 
the mantle, a very large foot bent in the middle, and with its 
point directed forwards; and two short or but moderately long 
tubes. 
Numerous species of cardia are found upon the coast of 
France, some of which are eaten, such as the C. edule, L., 
