156 
Ocean. Two fossil species are described by Lamarck, 
both of which are found in the more recent formation 
above the Chalk; one at Grignon, and the other at 
Granville. Neither of them are so gibbous as the re- 
cent one. Several others are now known. 
‘“Whether the shells of this genus be covered with an 
epidermis in their natural state or not, we have no means 
of ascertaining ; there is, however, some reason for be- 
lieving this to be the case.” 
The above description is taken from my brother’s 
‘¢ Genera of Recent and Fossil Shells,’ No. 2. I have 
only to add, that the hinge teeth are unequal, that the 
anterior side is largest, and that the recent. species is 
nearly colourless. 
CORBIS levis. 
TAB. DLXXX. 
Spec. Cuar. Transversely oval, elongated, rather 
gibbose, smooth except a small portion of the 
posterior extremity which is transversely undu- 
lated or rather imbricated ; margin entire. 
In the general form of the valves and the disposition of 
the muscular impressions, this agrees well with the ge- 
nus Corbis: the hinge is somewhat different, but as one 
of the remote teeth is worn away, and the whole cannot 
be relieved from the stone, we will not venture to say that 
it is sufficiently different to characterize a new genus. 
Collected many years ago by G. E. Smith, Esq., from 
the Sandy Limestone at Marsham Field, near Oxford. 
A second specimen has not been found. 
