PECTEN. 303 



in the Frith of Forth, six varieties of the Pecten o-pcrctilaris, according as the 

 prevailing colour is brown, purple, yellow, or white variegated with blotches or 

 undulated markings of some colour different from the general hue ; rarely does it 

 occur of a pure white. Pecten i-arius, from the west coast, varies in like manner, 

 and among its colours presents a pale-slate variety, with white markings. 

 Pecten sinuosus presents similar changes, but has not been observed pale purple, 

 and is rarely pure white. He distinguishes no fewer than eighteen colour- 

 varieties of Pecten ohsolctus, seven of which are white, four either pure or 

 variously marked with purple, brown, and yellow ; seven, purple, either plain or 

 variously marked with white, yellow, and brown ; three, orange, or orange and 

 white ; and one in which all the colours are equally mingled. 



P. IsLANDicus, Miiller. 



Free, not marbled, set with from fifty to a hundred small but 

 distinct ribs, which are not prickly, but armed with erect and 

 peculiarly crowded vaulted scales. 



Lister, Hist. Conch, pi. 1057, f. 4. — Seba, Mus. vol. iii. pi. 

 87, f. 7. 

 Pecteyi Islandicus, MtJLLER, Zool. Danic. Prodr. (1776), p. 248, No. 2990. — 

 TuRT. Dithyra Brit. p. 216. — Fleming, Brit. Animals, p. 

 385. — Macgilliv. Moll. Aberd. p. 226. — Brit. Marine 

 Conch, p. 1 19.— Brown, lllust. Conch. G. B. p. 72, pi. 24, 

 f. 3. — 0. Fabric. Fauna Greenland, p. 415. — Chemn. 

 Conch. Cab. vol. vii. pi. 65, f. 615, 616. — Lam. Anim. s. 

 Vert. (ed. Desh.) vol. vii. p. 145. — Say, American Conch, 

 pi. 56, f. 1. — Sowerby, Thesaur. Conch, vol. i. p. 75, pi. 

 17, f. 159, 160, 165. — Gould, Invert. Massach. p. 134, f. 

 87. — Hanl. Recent Shells, vol. i. p. 284. 

 Ostrea chmabarina. Born, Index Mus. Caes. (1778) p. 87; Mus. Caes. Vind. p. 

 103.— DiLLW. Recent Shells, vol. i. p. 256, 

 „ Idandica, Gmelin, Syst. Naturae, p. 3326. — Turt. Conch. Diction, p. 

 258.— Index Testaceolog. pL 10, f. 21. 

 Pecten Pealii, Conrad, American Marine Conch, p. 12, pi. 2, f. 2. 

 Encyclopedie Mt'thodique, Vers, pi. 212, f. 1. 



Notwithstanding- that of the many supposed British 

 individuals of this fine shell we have never seen a single 

 individual which did not exhibit a fossilized appearance, 

 we have preferred classing the P. Islandicus among our 



