Anomia. MOLLUSC A. OSTREAD^. 395 



Ostrea sylvestris, List. Conch, t. ccv — A. elect. Linn. Syst. i. 1151. 

 Turt. Biv. Brit. 227- t. xvii. f. 8, 9 — West coast of Ireland, Dr Tur- 



ton. 



About an inch and a quarter in diameter ; colour bright transparent yel- 

 low inside and out ; surface irregular, but not rough, plaited or scaly ; beak 

 pointed, not quite terminal ; the under valve flat, and scale-like, with a large 

 interrupted perforation. 



- 390. A. ephippium. — Shell orbicular-oval, rather rough, 

 wrinkled and plaited at the margin, and partly within. 



Ostreum parvum, List. An. Aug. 181. Conch, t. 204. An. Eph. Linn. 

 Syst. i. 1150. Mont. Test. Brit. 155. Turt. Biv. Brit. 227. t. xviii. 

 f. 1, 3. — On rocky coasts, common. 



Sometimes three inches in diameter, more or less pearly, and tinged with 

 green ; surface more or less ribbed longitudinally, and becoming scaly with 

 age ; operculum oval, large, thick, rough. 



391. A.cepa. — Shell oboval, flattish, rough; rosy -red within, 

 but not pearly. 



Linn. Syst. i. 1151. Turt. Biv. Brit. 228. t. xviii. f. 4.— Rocks at low 

 spring-tides in Torbay, Dr Turton. 



Length 2, breadth ] h inches, oblong, inclining to oval, rather flat, with a 

 rough but not an undulating surface ; beaks terminal ; the under valve thin 

 but not scaly. 



392. A. squamula. — Shell somewhat orbicular, smooth, trans- 

 parent, and horn-coloured. 



Linn. Syst. i. 1151. Mont. Test. Brit. clvi. and Dlxxxi. Turt. Biv. Brit, 

 ccxxix. t. xviii. f. 5, 6, 7 — On stones, shells, and sea-weeds. 



Diameter about half an inch ; flat, or a little tumid about the beaks, and 

 smooth. The substance is always thin and brittle ; the plug of attachment is 

 tendinous, seldom hard at the base, with a testaceous termination. 



393. A. undulata. — Shell rounded, or oblong, with longitu- 

 dinal rounded striae, and a triangular cavity on the under valve, 

 beneath the hinge. 



Ostrea subviridis, List. Conch, t. ccii. — O. striata, Mont. Test. Brit, cliii. 

 and dIxxx. — An. und. ib. 157. Turt. Brit- ccxxx. t. xviii. £ 8, 9, 10. 

 — On old shells and the crevices of rocks. 



Diameter upwards of an inch ; variable in figure and consistence ; margin 

 crenate, inside iridescent ; on one side of the perforation in the under valve, 

 is a triangular striated cavity ; the plug terminates in a thin oval layer, 

 strongly striate transversely, and crossed with fine longitudinal lines. 



« 394. A. -punctata. — Shell orbicular, with raised dots on the 

 upper valve, and concave ones on the under valve. 



Turt. Biv. Brit, ccxxxi. t. 18. f. 11. — On crabs and shells, on the south 

 coasts of England. 



Diameter about half an inch, thin, transparent, purplish white ; a little 

 truncate at the base ; beaks terminal. 



— 395. A. cylindrica. — Shell oval, somewhat cylindrically con- 

 vex, and transversely rugged, with the beak curved backwards. 



