OpL 



OpPl 



>OpL 



D 



FIG. 58. Sections through the otic lobe of embryos. A and B, trans- 

 verse sections intersecting the left optic lo'be of two embryos of Stage 

 XII ; C, of Stage XIII-XIV. D, tangential section through one of the 

 optic lobes of a newly hatched embryo (Stage XV), x 290. 



