54 PECTINID^E. 



strite: cohur red, pink, yellow, purple; brown, and rarely 

 milk-white, with streaks or blotches variously disposed : 

 margins rounded in front and at the sides, and notched or 

 indented by the ribs, sloping abruptly to the beak on each side 

 from a little above the middle ; upper side of the slope on the 

 right hand of the lower valve toothed or serrate as in the 

 last species: beaks prominent : ears unequal and formed as in 

 P. pusio ; the right-hand one of the lower valve projects 

 beyond and slightly overlaps the opposite ear of the upper 

 valve ; their markings and the byssal notch are the same as in 

 the last species, as well as the cartilage, ligament, and internal 

 structure ; but the muscular scars are more distinct. L. 1-85. 

 B. 1-65. 



Yar. 1. purpurea. Shell larger, broader, and natter : colour 

 purplish-brown marbled with yellow. 



Yar. 2. nivea. Shell of the same shape as the last variety, 

 and having about 45 ribs : colour snow-white, sometimes tinged 

 with purple, or more rarely orange, yellowish, purple, or brown 

 of different shades. P. niveus, Macgillivrav, Edinb. Nat. & Phil. 

 Journ. xiii. p. 166, pi. 3. f. 1 ; F. & H. ii. p. 276, pi. L. f. 2, 

 and (animal) pi. S. f. 3. 



Habitat : Equally common with the last species, and 

 in similar situations; but it does not appear to have been 

 found on these coasts north of the Orkneys, whence 

 a white variety has been procured by the Rev. Dr. Smith 

 of Old Aberdeen. The range of depth varies from low- 

 water-mark at spring-tides to 40 fathoms. Yar. 1. Fal- 

 mouth harbour and off Portsmouth (J. G. J.) ; Cork 

 harbour (Humphreys); Bantry Bay (Barlee). Var. 2. 

 Western coasts of Scotland, in 3-25 fathoms, on Lami- 

 naria saccharina and occasionally attached to stones; 

 Glengariff, Bantry Bay (Barlee). As a fossil or subfossil 

 this species is found in the upper tertiaries of the Bel- 

 fast, Clyde, and Sussex beds. Abroad it is distributed 

 in every sea from Bergen (Sars) to theiEgean (Forbes); 

 and according to Weinkauff it is not uncommon on the 

 Algerian coast. 



