Plate XII. 



Vol. IV. 



Drawings after Simrotli. 



Fig. I Eye of Helix pomatia drawn back into tentacle 

 — c cornea, b lens, r retina, tn tentacularnerve, on optic 

 nerve. Fig. 2 Otocyst of Cyclas cornea — c capsule, 

 /?/ nervous layer, <:/ cellular layer. Fig. 3 Ganglia of 

 Anodon with otocyst — c^ cerebral ganglion, «« auditory nerve, otocyst, 

 pg pedal ganglion. Fig. 4 Nerve collar, showing auditory organs in Helix 

 hortensis, (after Leydig) — otocyst. 



