Pecten. MOLLUSCA. BIVALVIA. 383 



PECTENID^. 



Gen. XCIV. PECTEN. Scallop.— Shell suborbicular ; 

 beaks approximate ; ligament internal, seated in a triangu- 

 lar cavity, a byssus issuing under the ear of the right valve ; 

 foot small, pedunculated ; mouth with branched tentacula. 



* Ears of the shell equal, or nearly so. 



— 371. P. maximus. — The left or upper valve flat, depressed 



towards the beak, the ribs rounded and striated longitudinally. 



List. An. Ang. 184. Conch, t. clxiii. — Ostrea maxima, Linn. Syst. i. 

 1144.— P. max. Penn. Brit. Zool. iv. 99. t. lix. f. 61. Mont. Test. 

 Brit. 143. Turt. Bev. 207 Gregarious on many parts of the coast. 



Length about 5 inches ; under valve whitish, upper valve variegated with 

 brown; ribs 12 to 16, longitudinally grooved and transversely striated. 

 Dredged and used as food ; it is said by old fishermen, to be taken in great- 

 est quantity after a fall of snow. 



— 372. P. JacobcBus. — The upper valve flat, depressed towards 



the beak, the ribs rounded and destitute of longitudinal strise. 



P. magnus, List. Conch, t. clxv. — Ostrea Jac. Linn. Syst. i. 1144— P. 

 Jac. Penn. Brit. Zool. iv. 100. t. lx. f. 62. Mont. Test. Brit. 144. 

 Turt. Biv. 208.— On the coast of England, rare. 



Length about 3 inches ; lower valve white, upper valve rufous ; ribs about 

 16, in the upper valve rough, subquadrangular, with a few longitudinal 

 grooves, the interstices nearly smooth ; the ribs in the lower valve rounded, 

 and, together with the grooves, transversely striated. 



— 373. P. opercularis. — The left valve convex; ribs rounded, 

 nearly smooth. 



P. tenuis, List. An. Ang. 185. Conch, t. cxix. — P. oper. Linn. Syst. i. 



1147-— P. subrufus, Penn. Brit. Zool. iv. 100. t. lx. f. 63 P. oper. 



Mont. Test. Brit. 145. Turt. Biv. Brit. 209. and P. subrufus, p. 210. 

 —Common on oyster beds. 



Breadth from 2 to 3 inches ; coloured plain or variegated ; ribs about 18, 

 the whole shell obsoletely striated longitudinally, and finely striated trans- 

 versely, especially in the furrows. 



374. P. lineatus. — The left valve convex ; a red line along 

 the rough ridge of each rib. 



(Da Costa, Brit. Conch. 147. t. x. f. 8.) Pult. Dorset. 36 — Ostrea lin. 

 Don. Brit. Shells, t. cxvi Southern coast of England. 



This shell is smaller than the preceding, the sides do not rise quite so 

 high towards the ears ; and the ribs are much finer. It seems to have been 

 first noticed by Dr Pultney. Dr Turton considers it as a variety of P. oper- 

 cularis. 



