304 



C. U. Ariens Kappers 



and Xautilus. The small opening would give it the faculty of producing 

 reversad images in consequence of the diverging course of the intraoadar 

 rays and this diverging direction of ?-ars, coming from a narrow pupil 



Monoapertural 

 / ^ eve of Man. 



Fig, 29. — Dorsally; Convexarrangment of ihc perctpting cells inthe pluriapertural 

 ej'c of insects. Ventrally: Concave aiiangment in the mono apertural eye of a 



vertébrate. 



according to the rules of phototaxis, will cause a concave arrangement of 

 the neuroepithehum. 



This phototropic formation of the hollow eye includes the meeting of 

 the neuroepithehum and the pigment layer, which phototropically is 

 attracted to it. 



Now there seems to be some truth at the bottom of this theory, since 

 it explains why the concave eye occurs so in all sorts of animáis of different 

 classes, where the eye Hes beneath the bodywall, the concave form 



