298 THE KETINA, BY MAX SCHULTZE. 



coloboma, must be obtained from numerous and exact ophthal- 

 moscope examinations of cases in which this arrest of develop- 

 ment has occurred. Here also there are relations in respect to 

 the development of the pigment epithelium from the external 

 lamina of the primary eye vesicle to the development of the 

 choroidal tissue that are quite unknown. 



