106 MAKKKTAI'.LK KKITISH MARINE FISHES 



and then passes on to the same side as the other eye. It is in 

 this way that these fishes come to have two eyes on the upper 

 side of the head, and the change takes place at about the time 

 when the little fish abandons the habit of swimming freely in 

 the water and takes to lying on the ground. The most im- 

 portant or final changes in the transformation of the larval fish 

 take place when it is between two and three months old, and 

 although the fish at three months old may still differ in certain 

 details from those which are older it is generally perfectly 

 recognisable as belonging to its particular kind. 



