Williams. — Eye of Flounder. 



PLATE 4. 



( Pseudopleuronectes americanus.) 



Fig. 18. Anterior face of a cross section through the head of a fish of Stage III. 

 XIOO. 

 Note. — 06. inf. s. should have been obi. inf. s. 

 Fig. 19. Portion of a slanting cross section through cerebral lobes and dienceph- 

 alon. X 100. 

 Note. — The letters n. opt. s. in this figure should be changed to tr. opt. clx. 

 Fig. 20. Frontal section through habenulas and geniculate bodies. X 100. 

 Fig. 21. Parasagittal section through geniculate body and optic tract. X 100. 



