18 CARDIUM. 
CAPRI'NUS. Montf. Appears from the figure to bea Heurx. 
CAPSA. Brug. Fam. Nymphacea, Lam. Deser. Equivalve 
transverse, subequilateral, subtrigonal; cardinal teeth, two in 
one valve, one notched in the other; lateral teeth remote, 
obsolete; ligament external; muscular impressions two in each 
valve; impression of the mantle with alarge sinus. Obs. This 
genus is so nearly related to Donax, that it is difficult to distin- 
guish it at first sight. The Capse, however, have not the 
short, plane, straight posterior side, the distinct lateral teeth, 
nor the crenated margins which characterize nearly all the 
Donaces, They are known from Erycina, by not having the 
pit in the hinge for the ligament. Fig. 109. C. Brasiliensis. 
CAPULUS. Montf. Piterorsis, Lam. 
CARDIA’CEA. (Cardiacées. Lam.) A family of the order Con- 
chifera Dimyaria, Lam, containing the genera Cardium, Car- 
dita, Cypricardia, Hiatella, Isocardia, and others enumeraed in 
explanation of figures 122 to 130. 
CARDINAL TEETH. The teeth upon the hinge, immediately 
under the umbones of bivalve shells, as distinguished from the 
lateral teeth, which are placed at a distance on either side. In 
Venus, fig. 119, the cardinal teeth are marked by the letter e. 
CARDISSA. Sw. A genus composed of such species of Car- 
pium as are heart-shaped, having the short side truncated. Ez. 
Cardium Dionzum, fig. 122. 
CARDITA. Brug. Fam. Cardiacea, Lam. Submytilacea, Bl. 
Deser. Equivalve, inequilateral, ovate, subquadrate, or oblong, 
marked externally by ribs radiating from the umbones and form- 
ing a crenated margin within; cardinal teeth, in one valve, one, 
long, thick, oblique, another short, more straight; in the other 
valve one, long, oblique, thick; muscular impressions, two, 
rather oval; impression of the mantle not sinuated. Obs. 
This description includes Lamarck’s genus Venericardia, which 
although consisting of the more oblong species, are not con- 
sidered sufficiently distinct to justify a continuance of the 
separation. Cypricardia is distinguished by a remote lateral 
tooth. Fig. 124, Cardita Calyculata. 
CAR’DIUM. Linn. Fam. Cardiacées, Lam. Conchacea, Bl. 
Descr. Equivalve, subequilateral, sometimes gaping posteriorly, 
ornamented externally by ribs radiating from the umbones ; 
cardinal teeth, two in each valve, locked into each other cross- 
wise; lateral teeth two in each valve, remote ; muscular impres- 
sions two in each valve, remote; impression of the mantle entire ; 
ligament external, round. Obs. Although this genus includes 
many remarkable forms, the characters are so easily defined 
that there is no difficulty in distinguishing it from any other 
genus. Fig. 122.C. Maculosum. Fig. 123*. C. Greenlandicum, 
Apuropira, Lea. Fig. 123**. C. Hemicardium. Gen. Hem- 
CARDIUM. 
