PECTEN. 275 



below. The angle of the larger auricle is acute, of the 

 smaller one obtuse. 



The most usual painting is livid or purplish chocolate 

 colour, rufous brown, orange, red, and yellow, generally 

 mottled, especially towards the umbones, with cloudy 

 patches of white, and not unfrequently in the darker ex- 

 amples with the echinations of a more orange tint than 

 the prevailing ground-colour. The young are often of an 

 uniform red, or are pale with streak-like patches of liver 

 colour or rufous. The internal colouring is similar to that 

 of the exterior but of a paler hue : the hinge-margin is 

 not plicated. A beautiful lilac variety is obtained in North 

 Britain, and a pure white one is occasionally taken in 

 the Firth of Forth. Specimens are sometimes met with 

 (these are usually odd valves), more than two inches and 

 a half broad and of nearly the same length ; the more 

 common proportions (the young are always the less or- 

 bicular) are, however, an inch and a half in length, and 

 an inch and three-quarters in breadth. 



The animal has the margins of the mantle of consider- 

 able breadth ; their free edges are fringed with short white 

 tentacula, their fixed borders with both short and long 

 ones, the latter fewest, and ranged at regular intervals. 

 We have counted about eighteen of these long cirrhi, 

 which are usually of a pink hue, on each mantle-margin. 

 The mantle-margins themselves are very variable in co- 

 lour, sometimes pale pink mottled with white, sometimes 

 bright yellow speckled with orange and brown. The 

 ocelli are black, and more numerous than the long ten- 

 tacles. The body is of a pale cream or yellow hue ; the 

 branchiae of a fawn colour. The foot is short, narrow, 

 and white. The mantle-edges lining the auricles have 

 short cirrhi only. 



