74 pectinid^:. 



rarely, the colour is white, with an orange tint at the beaks : 

 margins semicircular in front and sloping at the distance of 

 about one -fourth from the hinge -line at an angle of 30 degrees 

 to the beaks ; byssal slope not notched or serrate : beaks small 

 and not prominent in full-grown specimens : ears exactly equal 

 on the upper valve and nearly so on the other valve, furnished 

 with a few ribs or striae which radiate from the beaks ; byssal 

 notch closed in the adult state : liinge-line straight, rather 

 more than half the breadth of the shell : cartilage large, thick, 

 and strong: ligament narrow and rather slight: hinge-plate 

 broad, closely and microscopically striate across ; transverse 

 rib strong and raised on each side of the broad cartilage-pit ; 

 in the lower or deeper valve are two or three short oblique 

 ribs, which diverge from above the cartilage-pit towards the 

 sides in wave-like lines : inside glossy, tinged more or less 

 deeply with reddish-brown, fluted as in P. opercularis, and 

 having similar shoulders or ledges on the posterior slopes to pre- 

 vent contact at the hinge-area : muscular scars well marked, 

 especially on the upper valve. L. 4*5. B. 5. 



Habitat : Nearly everywhere, and often gregarious 

 on banks, in 7-78 fathoms. It is also not uncommon 

 in all our upper tertiaries, both new and old. Its foreign 

 range comprises all the sea-bed lying between Norway 

 and the Canaries ; and, according to Sars, it occurs with 

 arctic shells in the " postglacial " beds of Christiania. 



If the oyster is the king of mollusks, this lias a just 

 claim to the rank and title of prince. In Lister's time 

 they were held in nearly the same esteem; and the 

 great scallop is even preferred by some, although from 

 its luscious quality it is not so provocative of appetite. 

 I have not heard of its being eaten raw in this country. 

 In the fish-markets of the north of France it is called 

 " grand'-pelerine," " gofiche," or " palourde." In the 

 south of England it shares with P. opercularis the name 

 of " frill," and in the north that of " clam." According 

 to Athenseus, this or an allied species (P. Jacobaus) was 

 used by the ancients for medicinal purposes, as well as 



