226 MALACOZOA. TROPIOPODA. LAMELLIBRANCHIATA, 



6. Pecten Pusio. Dwarf Scallop. 



Shell ovate, or ovato-oblong, equivalve; both valves with 

 about forty alternately large and small, regular, compressed, 

 obtuse, somewhat undulated or nodose ribs, becoming more or 

 less scaly or spinous at the margin ; the ears very unequal, 

 one of them being almost obliterated ; the colours various, 

 generally red or purplish and white or yellow. The greatest 

 diameter about three-fourths of an inch. 



This shell, which is very common in the outer Hebrides, and 

 on some of the western coasts of Scotland, appears to be of 

 rare occurrence in our district, where, on the coast of Buchan, 

 it was found in September, 1842, by Mr. Alexander Murray. 

 It seems to me perfectly distinct from either Pecten varius, or 

 Pecten distortus, but is much more nearly allied to the latter. 



Ostrea Pusio. Lirm. Syst. Nat. 1146. Pecten Pusio. Turton, 

 Brit. Biv. 215. PI. 17. f. 2. Pecten Pusio. Flem. Brit. Anim. 385. 



7. Pecten Islandicus. Icelandic Scallop. 



Shell sub orbicular, subinequilateral, subequivalve, with 

 about forty crowded, narrow, convex, transversely lamelloso- 

 striate, subscabrous ribs, which subdivide as they proceed from 

 the umbones, so as to amount to a hundred and twenty or 

 more at the margins ; auricles unequal, similarly ribbed ; 

 lower valve externally yellowish- white ; upper variously tinged 

 with reddish-yellow, rose-colour, purple, or chestnut; inner 

 surface glossy, pearly, more or less ribbed, with very marked 

 impressions. Diameter four inches or more. 



Dead valves very common in deep water, off the coast at 

 Aberdeen and Gamrie. No live individual hitherto found. 



Pecten Islandicus. Flem. Brit. Anim. 385. Pecten Islandicus. 

 Turt. Brit. Biv. 216. Pecten Islandicus. Lamk. Syst. vi. 258 ; 

 Ed. 2. vii. 145. 



8. Pecten obsoletus. Striulate Scallop. 



Shell triangular-orbicular, thin, subdiaphanous, with the 

 valves little convex, one less so, with very obsolete longitudi- 

 nal ridges, and toward the margin numerous striae, and mi- 

 nutely shagreened all over with longitudinal striulae, diverging 

 toward either side, and crossed by fainter striulse ; the ears 

 very unequal, the larger with a few prominent straight, longi- 

 tudinal, and numerous transverse, undulated striae ; the colour 

 various, whitish, pinkish, purple, brown, yellow, orange, trans- 

 versely banded, or spotted, patched or clouded with red, 



