97 



According to Chilton, "94, the degeneration of the eyes of crustaceans 

 may follow one of three lines. We may have — 



-:^ 



1. Total atropliy of optic lobes and optic nerves, v\'ith or witliout the 

 persistence in part of the pigment or retina and the crystalline lens. 



2. Persistence of optic lobes and optic nerves, but total ati'ophy of 

 the rods and cones, retina (liigment), and facets, or, 



