38 



THE STORY OF LIFE IN THE SEAS. 



In the course of their development the Soles 

 undergo very extraordinary changes in form to 

 reach the perfectly flattened condition of the 

 adult stage. These changes affect many of the 

 organs of the body, but perhaps the most in- 

 teresting of all is the history of the eyes. In 

 the young Soles, which swim almost vertically, 

 like the majority of fishes, there is one eye on 



FIG. 10. The Angler. 



each side of the head, but as they grow older 

 and gradually take to the habit of swimming on 

 one side, the eye of that side sinks down into 

 the head, and rotating as it goes passes through 

 to the other side. This process naturally leads 

 to a considerable distortion of the skull, so that 

 the bones of the adult Sole show as complete a 



