308 



JAMES ROLLIN SLONAKER 



The inner segments of the rod-and-cone processes are broad 

 and blunt. Their nuclei occupy their inner ends. At the outer 

 ends of these blunt processes are very short processes, the begin- 

 ning of the outer segments. No distinction can be made in 

 these elements in my sections as to whether they are rods or 

 cones. 



TABLE 6 



Showing the total thickness of the retina at the ora serrata and the axial regions, the 

 computed area of the total retina, and the axial and equatorial diameters of the eye 

 at the ages indicated. 2 to 12, number of days incubation; H-2, hatched two days; 

 H-4. hatched four days; H-fl, young just flying. All measurements are in 

 millimeters 



The ganglion cells have developed dendritic processes and 

 appear to have reached the complete differentiation seen in the 

 adult. 



The five divisions of the inner molecular laj^er described by 

 Ramon y Cajal are more conspicuous. 



The amakrin cells of the inner nuclear layer are separated 

 from the bipolar cells by a narrow lighter region. 



Five to six days after hatching, all of the layers of the retina 

 have practically reached the condition of the adult, excepting 

 the rod-and-cone layer. The outer segments of these elements 

 have increased in length, but have not reached the adult con- 



