PART II. MACROTBACHIA. TELLIiS'ID^E. 36$ 



the umbones are remote ; the ligament placed in an 

 external slit ; the lateral teeth very short and small, 

 and the cardinal teeth nearly obsolete. 



S. Sprengleri. En. Meth. 252. f. 3. 



Hemimactra Sw. General form of Mactra ; but the 

 cardinal teeth entirely wanting ; cartilage internal, 

 central, in a large triangular cavity ; lateral teeth -2-, 

 distinct, lamellar, striated : connected to the Glycu- 

 neri. 

 H. gigantea Lam. v. 472. No. 1. grandis Sw. Sp. Nov. 



Crassatella Lam. Shell solid, heavy, not gaping, more 

 or less rostrated ; hinge very thick ; cardinal teeth 4j 

 sub-angular, striated, and placed on one side ; imme- 

 diately beneath the umbones is a triangular cartilage ; 

 lateral teeth obsolete: representing Pandora, Trigonia, 

 Placuna, &c. 

 C. Kingicola Lam (fig. 1 18. a.) rostrata. Sow. Man. f. 84. 



GLYCIMERIS Lam. Oblong, transverse ; both extre- 

 mities gaping ; cardinal and lateral teeth entirely 

 wanting ; but the hinge margin very thick ; ligament 

 large, external : representing Solenimya, and con- 

 nected to Solen by Novaculina* 



G. Siliqua. Sow. Gen. (fig. 118. b,c.) 



FAMILY TELLINIDyE. Solid and close Bivalves. 



Shell never gaping t ; equivalve ; the margins thickened 

 and solid ; rarely covered with an epidermis ; cardinal 

 and lateral teeth well developed. 



SUB-FAM. i. CYCLING. 



Animal generally fluviatile ; shells covered by an epi- 

 dermis. 



CYCLASJ: Lam. Shell thin, transversely ovate, equila- 



* The four other sub-genera are unknown. t Except in Psammobia. 

 % Including Pisidum. 



