1 66 OYSTERS, AND ALL ABOUT THEM. 



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 me more distinct. Length 1*85, breadth 1*65. 



Var. i, purpurea. Shell larger, broader, and flatter: 

 colour purplish-brown, marbled with yellow. 



Var. 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, 

 Macgillivray, Edinb. Nat. and Phil. Journ. 13, p. 166, pi. 

 3, f. i ; F. and H. 2, p. 276, pi. 50, f. 2, and (animal) pi. 

 S. f. 3. 



HABITAT : F. England and Ireland. E. Christian- 

 sund southwards (Sars). 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. The range of 

 depth varies from low-water mark at spring tides to 40 

 fathoms. Var. i. Falmouth Harbour and off Portsmouth 

 (J- G. J.) ; Cork Harbour (Humphreys); Bantry Bay 

 (Barlee). Var. 2. Western coasts of Scotland, in 3-25 

 fathoms, on Laminaria 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 

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

 in every sea, from Bergen (Sars) to the ^Egean (Forbes) ; 

 and according to Weinkauff, it is not uncommon on the 

 Algerian coast. 



In the north of France it is called " Petite-Vanne ;" 

 and Collard des Cherres says that it is eaten in Brittany, as 

 well as other kinds of scallops. The pallia! tentacles or 



