THE EYE OF PECTEN. 



59 



groups on the mantle-edge of P. opercularis and also of 

 the individual variation in this species (the specimens were 

 from the Irish Sea). 



It will be seen from these figures that there is no relation 

 between the size of the animal and the number of eyes, though 

 if the first five only had been taken the reverse would have 

 appeared to be the case. Possibly Carriere only examined a 

 few and chanced to get an accidental series. No one appears 

 to have examined the very small eyes occurring with the 

 large ones. I sectioned some of those taken from the right 

 mantle-lobe of Pecten jacobaeus and found that they 

 agreed in every respect with the large eyes of the left lobe, 

 all parts being represented and in the normal positions. The 



