PLATF] 3 



EXPLANATION OF FIGURES 



Figures 17 tu '22, wliich are photographs showing the iriHucuce of temperature 

 on the distribution of the retinal pigment of the frog (adults and larvae), are all 

 at a magnification of 170 diameters. The larval Rana catesbiana, from which 

 figures 20 to 22 were made, had a total body length of 7.0 cm. A Leitz /o homo- 

 geneous immersion objective was used in making figures 23 and 24, which are 

 magnified 715 diameters. 



17 R. pipiens (adult), 3°C. in the dark. 



18 R. pipiens (adult), 18°C. in the dark. 

 1!) R. pipiens (adult), 33°C. in the dark. 



20 R. catesbiana (larva), 3°C. in the dark. 



21 R. catesbiana (larva), 16°C. in the dark. 



22 R. catesbiana (larva). 32°C. in the dark. 



23 Carassius, 27°C. in the dark. 



24 Carassius, 3°C in the dark. 



196 



