MALACOZOA. TROPIOPODA. LAMELLIBRANCHIATA. 231 



they have grown in the opposite direction to that of the Pecten 

 on which they have lived. This property which the Anomia? 

 have of assuming and retaining the impression of the foreign 

 bodies to which they adhere ought to render us very circum- 

 spect in defining species." 



Common on stones, live and dead shells, Crustacea, and 

 tangles. 



Anomia Ephippium. Linn. Syst. Nat. i. 1150. Anomia Ephip- 

 pium. Penn. Brit. Zool. iv. 109. PL 62; Ed. 2. iv. 232. PI. 65. 

 Anomia Ephippium. Flem. Brit. Anim. 395. Anomia Ephippium. 

 Turt. Brit. Biv. 227. PL 18. f. 1 , 2, 3. Anomia Ephippium. Lamk. 

 Systvi. 1, 226; Ed. 2. vii. 273. Anomia patellaris. Lamk. Syst vi. 

 2, 227; Ed. 2. vii. 273. Anomia Ephippium. Mont Test. Brit. 155. 



2. Anomia Squamula. Thin Scale-Oyster. 



Shell roundish, very thin, semitransparent, white ; the upper 

 valve little convex, even, with the beak small, glossy, rattier 

 pointed, and projecting beyond the margin; lower valve ex- 

 tremely thin, glossy, uneven, concentrically striated, with the 

 aperture circular; the opercular plate extremely thiii. Dia- 

 meter nearly an inch. 



On live and dead shells, crabs, and stones, along the rocky 

 coasts, and often in deep water. 



Anomia Squamula. Linn. Syst. Nat. i. 1151. Anomia Squa- 

 mula. Turt. Brit. Biv. 229. PL 18. f. 5,6,7. Anomia Squammula. 

 Penn. Brit. ZooL iv. 109; Ed. 2. iv. 232. Anomia Squamula. 

 Mont. Test. Brit. 156. Anomia Squamula. Flem. Brit. Anim. 

 395. Anomia, Squamula. Lamk. Syst. vi. 1, 228; Ed. 2. vii. 275. 



3. Anomia unduldta. Undulated Scale-Oyster. 



Shell roundish, moderately thin, white or reddish ; the upper 

 valve convex in various degrees, concentrically squamoso-ru- 

 gose, radiated with irregular undulated slender ribs, running 

 out a little on the margin, the umbo convex, not projecting, 

 the inside generally greenish, glossy, or somewhat iridescent, 

 with a subcentral opaque white patch ; the lower valve irre- 

 gular, thin, with the aperture large, communicating with the 

 margin by a slit. Diameter about an inch and a-half. 



Not uncommon on shells, Crustacea, and stones, off Aber- 

 deen. Found also by Mr. Alex. Murray, near Peterhead. 



Anomia undulata. Gmel. Syst. Nat. 3346. Anomia undulata. 

 Mont. Test. Brit. 157. PL 4. f. 6. Ostrea striata. Mont. Test. 

 Brit. 153. Anomia uudulata. Turt. Brit, Biv. 230. PL 18. f. 8,9, 

 10. Anomia undulata. Flem. Brit. Anim. 395. 



