OSTREA. 281 



inhabits 



Shell about an inch long, and the length rather exceeds the 

 breadth ; very thin, brittle, whitish, and the inside glossy 

 silvery white ; the lower valve is somewhat longer and broader 

 than the upper. Schroeter in the same page of his Einleit- 

 ung has mentioned another somewhat similar shell, which 

 Gmelin has very imperfectly defined under the name of O. 

 papyracea. 



* # # # * 



With the Hinge composed of transverse fur- 



rows in a straight line. 



semiaurita. 77. Shell oval, slightly eared, 

 smooth, and the umbones ending in a short 

 incurved beak ; hinge oblique. 



Ostrea semiaurita. Linneeus Syst. Nat. p. 11 49. Schroe- 

 ter Einl. iii. p. 365. t. 9. f. 6. Gmelin, p. 3335. 

 Gualter, t. 84. f. H. 



Inhabits the Mediterranean. Schroeter. 



The shell figured by Schroeter for this species is described to 

 be an inch and a half long, and an inch and a quarter broad, 

 very thin, of a dirty olive colour, with a few undulated lon- 

 gitudinal white stripes. Dr. Solander considered the Lin- 

 naean O. semiaurita and O. Perna to be the same species, 

 and Gualter, t. 84. f. H., to which Linnaeus has referred for 

 the former, is very much like the latter shell. 



perna. 78. Shell oblong, with the umbones form- 

 ing an incurved lateral beak ; hinge oblique. 



Ostrea Perna. Linneeus Syst. Nat. p. 1149. Schroeter 



Einl. iii. p. 351. t. 9- f. 5. Gmelin, p. 3338. 

 Ostrea semiaurita. Chemnitz, vii. p. 250. t. 59. f. 579 and 



580. 

 Pedalion Perna. Solander's MSS. Portland Cat. p. 52. 



lot 1242. 

 Perna. Enc. Meth. t. 175. f. 1. 

 Lister Conch. 1. 199- f- 33, and t. 228. f. 63. Kkin Ost. 



t.8. f. 19 and 20. 

 Inhabits the Indian Seas. Linnaus. Coasts of Tranquebar, 



and the West Indies. Chemnitz. China. Humphreys. 

 Chemnitz has figured two shells which he considered to be va- 

 rieties of O. semiaurita, and both of these are referred to by 

 Schroeter and Gmelin for the Linnaean O. Perna ; the first 

 (fig* 5790 measures two inches aad two lines by one inch and 



