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. 



t Manuel de Malacologie, &c, p. 529. 



