200 TELLINA. 



laminae are crenated. Young shells are paler, thinner, 

 and somewhat diaphanous. Length half an inch, 

 breadth three quarters. 



Inhahits the South American rivers. 



We are indebted to Dr. Maton for our knowledge 

 of this singular shell, and for the use of his speci- 

 men, from which our figure has been engraved and co- 

 loured. There are three different views of a shell, in 

 the Encyclop. Method, pi. 302. f. 2. a. 2. b. and 2. c. 

 which resemble this but not sufficiently to pronounce 

 them the same. The peculiarity which at once distin- 

 guishes this species from others of the genus Tellina, is 

 the crenated lateral laminae, which are plainly to be 

 seen with the assistance of a lens. The French have 

 arranged shells of this description in a new genus, 

 under the name of Cyclas. 



