SEA-FISHERIES LABORATORY. 113 



It is hardly possible that the absence of the eye is 

 congenital since the optic nerve and the eye-muscles 

 could not have attained the development indicated. It is 

 possible, however, that a failure to form the lens in early 

 development may have led to this abnormality. In the 

 absence of the ectodermal invagination forming the lens 

 the bulbus oculi may have degenerated : there is no reason 

 why the optic nerve should have degenerated since the 

 trophic centre is in the brain. That this happened 

 seems, on the whole, more likely than that a traumatic 

 lesion led to the disappearance of the whole eye, since in 

 the latter case there ought to have been a much greater 

 development of scar tissue than the sections show. As it 

 is, there is nothing in them to suggest granulation tissue, 

 and the development of mucus-secreting cells in the 

 integument lining the empty orbit is very striking. 



