138 



THE EYE IN EVOLUTION 



ViGS. 101-3. — Representative Cupulate Eyes of a Moke Complex 



Type. 



Fig. 101. — The ocellus of the polychspte worm, 

 Nereis. 



C, cuticle ; Ep, epithelmm ; N, nerve fibres ; 

 P, pigment between the sensory cells ; R, 

 nucleated sensory cells provided with cilia ; 

 y, vitreous (after Hesse). 



Fig. 102.— The ocellus of the Cubo- 

 medusan, C'harybdea. 



L, cellular lens ; V, " vitreous 

 body " of the clear rhabdites of 

 retinal cells ; P, pigmented zone 

 of retinal cells ; R, retinal cells ; 

 N, nerve tissue with ganglion cells, 

 G (after Berger). 



ON 



CG 



Fig. 103. — The eye of Peripalns. 



Diagrammatic sagittal section of t}ie e\e ; partly depigmented to 

 demons; i ate details of the visual cells. 



C lea ; CG, cerebral ganglion ; Ep, hypodermis ; L, lens ; OG, optic 



ganglio; ')N, optic nerve ; R, rods ; V, visual cells (after Dakin). 



