112 THE STORY OF ANIMAL LIFE 



position, the friction caused by the ridges would 

 seriously delay the progress of the shell. 



Something must be added regarding the col- 

 ouring of the shell, which is vivid, corresponding 

 with that of the animal within. It is capable of 

 great variety, though perhaps not so great as in 

 some of the smaller Pectens. The predominant 

 shades are pink, crimson and yellow, either sepa- 

 rately or mixed ; that is to say, some shells are 

 pure pink, some almost pure yellow, some almost 

 pure crimson, while others present every imagi- 

 nable shade of pinkish yellow, reddish brown and 

 brownish crimson. Local variation of colour is 

 so marked that we may suspect the variations in 

 tint to be in some degree protective. The shell 

 also varies considerably in size and strength 

 according to the neighbourhood in which it has 

 grown. 



This scallop-shell is but one of many : a num- 

 ber of other species are found on our own shores, 

 and many others again in foreign seas. 



One shell of the English coast is very annoying 

 to the juvenile shell-collector who gathers speci- 

 mens on the shore. This is Pecten pusio, a very 

 small and delicate kind, with a raised pattern of 

 fine markings upon the ridges, which are very 

 narrow. A good specimen of the deeper valve is 

 common enough, but the shallow valve, if of any 

 size, is distorted into all manner of shapes, as if 

 it had been squeezed and crumpled. The dis- 

 appointing character of these specimens, from an 

 aesthetic point of view, is explained when we 

 learn that it not only lies on its shallow valve, 

 but becomes fixed in this position, instead of 

 hopping about freely like the P. opercularis. It 

 therefore has frequently to adapt its shape to the 



