SHELLS. 231 



" bleeding tooth," from the red appearance of the 

 teeth on the inner lip. We have also another species, 

 Nerita versicolor. Its shell is thick, transversely 

 sulcated, and tesselated vrith red and dark spots 

 in transverse rows ; inner and outer lip toothed, 

 and the latter striated within. 



The second family of the Pectinibranchiata are 

 the Capuloides. Cuvier divides this family into five 

 genera. AU of them have a widely open shell, 

 scarcely turbinate, without an operculum, and with- 

 out emargination or canal. Genus Crepidula is the 

 only representative of this family. The species known 

 here is the Crepidula onyw. This is a curious and 

 often a very beautiful shell, and of the most brilliant 

 colour — black in the inside, with the little half-deck, 

 as it may be called, of a beautiful white, and having 

 the margin of the shell tinged with a rich brown. 



The third family of the Pectinibranchiata are the 

 Succinoides. Cuvier groups this family into genera 

 according to the length of the sinus or canal (when 

 it exists), the greater or less width of the aperture, 

 and the various forms of the columella. 



The following genera belong to the Buccinoides, 

 viz. : 1. Genus Conus, which is the most beautiful, 

 most extensive, and most interesting of the spiral 

 and unilocular univalves. It contains shells remark- 



