MACTRA. 137 



it to be an inch and a half long, and allied to M . glabrata, 

 from which it differs in having the anterior slope distinctly 

 keeled, and the umbones more distant; it is a triangular, 

 thick, white, pellucid shell, and has the posterior slope rather 

 convex. 



corallina. 14. Shell triangular-rounded, pellucid, 

 whitish, with milk-white bands, and very ob- 

 tuse at both ends. 

 Mactra corallina. Linncsus Si/si. Nat. p. 1125. Chem- 

 nitz, vi. p. 223. t. 22. f. 218 and 219. Schroeter Einl. 

 iii. p. 76. Gmelin, p. 3258. 

 Bonanni Rec. 2. f. 53. and Kirch, f. 52. Gualter, t. 71. 

 f.'B. 

 Inhabits the Mediterranean. Linnaus. Coasts of Guinea, 



Chemnitz. Naples. Ulysses. 

 Chemnitz has described the shell which he has figured for this 

 species, to be nineteen lines long, and two inches broad ; 

 triangular, white, smooth, diaphanous, and truncated, both 

 at the anterior and posterior ends. Dr. Solander considered 

 the Linnaean M. corallina, to be only a Variety of M. solida, 

 and all the figures above referred to bear a considerable re- 

 semblance to some of its varieties, but are less strongly 

 marked with transverse ridges. 



lactea. 15. Shell sub-triangular-rounded, white, 

 somewhat diaphanous, and the umbones gib- 

 bous and tumid. 



Mactra lactea. Chemnitz, vi. p. 224. t. 22. L 220 and 221. 

 Gmelin, p. 3258. 



Mactra, No. 6. Schroeter Einl. iii. p. 83. 

 Inhabits the coasts of Tranquebar. Chemnitz. 

 Shell nineteen lines long, and twenty-six broad ; whitish, with 



milk-white bands, and differs from C. corallina, in being 



thinner, and more convex, and in having the umbones tumid. 



striata. 16. Shell triangular, white, with numer- 

 ous thick, smooth, crowded, concentric striae. 



Mactra striata. Chemnitz, vi. p. 225. t. 22,. f. 222 and 223. 

 Gmelin, p. 3257. 



Mactra, No. 7. Schroeter Einl. iii. p. 83. 



Inhabits 



Chemnitz's figure represents a shell about nine lines long, and 



eleven broad; whitish, with whiter bands, and strongly 



