PECTEN. 303 



in the Frith of Forth, six varieties of the Pecten operations, 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 rarins, from the west coast, varies in like manner, 

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

 Pecten sinuusus 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 obsoletus, 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. 

 Pecten Islandicus, Muller, 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 Groenland. p. 415. — Chemn. 

 Conch. Cab. vol. vii. pi. 65, f. 615, 616. — Lam. Aniiu. 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 cinnaharina, Born, Index Mus. Cses. (1778) p. 87; Mus. Cajs. Vind. p. 

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

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

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

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

 Encyclopedic Mtthodique, 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 



