I18 
P. OpsoLetus. Pen. 4. p. 222. t. 64. f. 3.—Don. 
t. 1. f. 2.—Mont. p. 149. §& Sup. p.57.—Turt. B. p. 
213. ¢.9. f. 6.—F. p. 385.—Ostrea O. Lin. T. 8. p. 
100.—D. p. 263.—Turt. D. p. 133.—Ost. Lzvis. 
Tin. T. 8. p. 100. ¢. 3. f. 5.—Equivalve, roundish- 
oval or oblong, purple reddish or yellowish (rarely 
clear white) often variously marbled or spotted ; the 
surface generally marked with raised ribs towards the 
broader end, more or less in number, which are 
sometimes defined by a deep transverse line separating 
them from the plain part, but always marked with 
fine and almost invisible longitudinal irregular and 
somewhat undulate striee over the whole surface. Torbay 
and English Channel. 
P. Varius. Pen. 4. p. 221 t. 64. f. 1.—Moné. p. 
146.—Lam. 47.—F. p. 384.—Ostrea V. Lin. 1146. 
-—Don. 1.¢.1. f. 1.—Lin. 7.8. p.97.—Dor.Cat. p. 38. 
t. 10. f. 1,2,4,5,8,9.—D. p. 260.—Turt. D. p. 130. 
—Da Cost. t. 10. f. 1,2,4,5,7,9 —Ch. f. 633,4.— 
List. t. 180, 181, and ¢. 189. f. 23.—Rounded-oblong, 
extremely variable in coloring, but not unfrequently 
brownish red, with about thirty-two rounded prominent 
radiating ribs, armed when perfect, with erect vaulted 
scales, the interstices very deep and not striated ; ears 
very unequal. 12.long. Hatremely Common. 
