TO GEOLOGY. 73 
pressed ; cavity of the shell very deep; margin minutely 
crenulate ; nacre somewhat pearly. 
Diam. 3-20ths, Length 5-20ths, Breadth 3-20ths, of an inch. 
Three views are given, the smallest being of the size 
of nature. 
Observations. ‘Three or four valves only of this curious 
little shell were received by me. The posterior part is 
exceedingly flat, resembling in this respect some of the 
Cardia. The depression of the anterior part is between 
the anterior margin and the beaks; hence the posterior 
margin differs from it, the one being subangular, the other 
curved. 
GENUS MYOPARO.* — (nobis.) 
Description. Shell cordate, equivalve ; beaks recurved ; 
a series of small teeth, transverse to the margin, on each 
side of the beaks, and placed on the margin; two large 
cicatrices. 
Observations. In its general appearance, this resembles 
the genus just described, and were it not for the teeth on 
either side of the beak, it would naturally take its place 
there. In the outline, and possession of an anterior series 
of teeth, it approaches the Catillus (C. Lamarckii) of Blain- 
ville,t which, however, has teeth on one side only. The 
* A piratical oar-galley. 
+ Manuel de Malacologie, &c. p. 529, 
