370 SHELLS AND SHELL-FISH. PART 11. 



teral ; cardinal teeth small; lateral teeth -?, long, 

 compressed ; ligament external, (fig. 1 19. &.) 

 C. rivicola. Sow. Man. f. 111. 



CYRENA Lam. Shell thick, transversely ovate, nearly 

 equilateral ; cardinal teeth ; lateral teeth 4r, short, 

 thick, obtuse ; fluviatile and marine, (fig. 119- ) 



C. Surnatrensis. Sow, Gen. 1 4. 



MEGADESMA Bowdich.* Shell thick, trigonal, nearly 

 equilateral ; cardinal teeth -J ; lateral teeth obsolete ; 

 hinge very thick ; ligament external. (fig.\\Q. e?.) 

 M. radiata. Sow. Man. f. 115. 



GNATHODON Gray. Shell transversely obovate, in- 

 equilateral ; bosses thick, prominent, remote ; car- 

 dinal teeth -1- lateral ~ ; cartilage internal, placed 

 by the side of the cardinal teeth. 



G. cuneatus. Sow. Man. f. 83. 



CUMINGIA Sow. Shell transversely obovate ; hinge 

 with a spatulate cavity filled by the cartilage ; car- 

 dinal teeth \, very small ; lateral teeth | ; marine : 

 leading to Erycina, and representing Amphidesma. 

 C. mutica. Sow. Man. f. 87. 



ERYCINA j" Lam. Shell always transverse, generally 

 cuneate, but rarely equilateral ; both valves closing ; 

 cardinal teeth ^, between which is the ligament ; 

 lateral teeth , one of which is lengthened, 

 striata. Sow. Gen. f. 2. plebeja. Ib. f. 3. 

 (.fa. 118. rf,.) 



* Galatheea of Lam. 



t This name should be changed, having been previously applied by 

 Fabricius to a large family of lepidopterous insects. Eryx may be used, as 



raonciUa to a, large laniiiy ui icpiuuui.ci 



preserving the same mythological idea. 



