No. 477] 



HISTOGENESIS OF RETINA 



627 



frog, the granules begin to appear ni the chick on the side of the 

 layer away from the retina and in the protoplasm V)etween the 

 nuclei, which shows them to lie of cvtoplasniic origin (P'lgs. S and 

 12). Cameron says that in the frog thev appear hrst on the side 

 ad]ommg the retina. As development proceeds and the nuclei 

 become farther apart these granules gradually fill all the cvio- 

 plasm of the pigment laver on the side tartliest troiii the retina 

 (Fig 9) It ^Mll also be notutd th it it \\n iin. tmu x .(.lolts 



nuu t th I, HUH . I .-, i n u. 1 t th Nt |li ini tn uiicrs 

 Mln.h hn dU <lo(lop tM.ni th( punuiulnu m I t m. n 1 iiiuird 



