180 
is very frequently found. Among the Hampshire fossils is a very curious 
cardium, C. porulosum, Brand, on the longitudinal costae of which are 
disposed thin, carinated, and crenulated plates, which are perforated 
at their base. C.discors, C. porulosum, G. asperulum, G. calcitrapoides, 
C. oblicuum, C. granulosum , C. lima , and C. heteroclitum, are given 
by Lamarck as the species found in the environs of Paris. 
CVII. Crassatella. An equivalved inequilateral, close bivalve. The 
hinge teeth, two, with an adjoining pit : the lateral teeth obsolete. 
The cartilage inserted in a pit formed in the hinge. 
The genera Crassatella, Lutraria, and Mactra, agree in having 
the cartilage of the valves interior, and attached to the hinge -pit of 
each valve ; but this genus differs from the other two, in there being 
no gaping when the valves are shut. 
C. tumida, PI. XIII. Fig. 2, much resembles a recent species of this 
genus, which was found at King’s Island, in the South Seas, by M. Pe- 
ron. The shells of this, as well as of some other species of this genus, 
acquire a considerable degree of thickness with age. One specimen 
which I possess, from Grignon, which is about three times the size of 
that which is here delineated, weighs nearly half a pound. C. lamellosa, 
Lam. has been supposed to be the same shell, which is figured by Bran- 
der, among the Hampshire fossils, as Tellina sulcata, Fig. 89 ; but the 
English shell differs, in its form, from the French one, according to 
the specimens in my possession : the English one terminating, at its 
anterior side, in a more determinately pointed rostrum than the French 
one does. This, however, may be only the difference of a variety. 
G. compressa, Lam. resembles the species just mentioned, except in 
being less elongated transversely, and in its ridges being much smaller 
and closer. Four more species, G. sulcata, C. gibbosula, C. laevigata, 
and C. triangularis, are found in the neighbourhood of Paris. 
CVIII. Paphia. A subtransverse inequilateral shell, with close 
valves, and having the cartilage internal. The pit for its insertion is 
under the beaks, between or beside the teeth of the hinge. 
