Pecten. 
MOLLUSCA. BIVALVIA, 
383 
PECTENIDiE. 
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 equals or nearly so. 
371. P. mawimus . — 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. 
37S. P. JacobcEus . — -The upper valve flat, depressed towards 
the beak, the ribs rounded and destitute of longitudinal strias. 
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. Twrt. 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- 1. 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. 
4 
