82 



University of California Publications in Zoology [VOL. 11 



I. EFFECT OF CHANGES IN LIGHT, HEAT, AND FOOD UPON 

 PIGMENTATION 



To determine the influence of light and heat upon the color 

 differences produced in the tadpoles by different foods, the fol- 

 lowing experiment was carried out. Eight dishes of tadpoles, 

 all from the same bunch of eggs, were arranged as shown below. 



Warm : 



In constant temperature, box (of 

 glass) kept at about 26.5 C. 



Cold: 



In north basement room. (The 

 temperature of this room varied 

 very little and was always con- 

 siderably below ordinary room 

 temperature.) 



In dark. 



(in black paste- 

 board box) 



In light. 



In dark. 



(in black paste- 

 board box) 



In light. 



a. fed on liver 

 Z>. fed on yolk 



'"c. fed on liver 

 d. fed on yolk 



re. fed on liver 

 /'. fed on yolk 



ff. 



I"- 



fed on liver 

 fed on yolk 



TABLE 16 



Length measurements of Sana tadpoles under different conditions of light, 

 temperature, and food. Measurements are average length of all the 

 tadpoles in a dish. Experiment began with eight tadpoles in each lot. 



Eana. Experiment started Feb. 10, 1912 



March 5 



AVERAGES 



Cold . 

 Warm 



Light 

 Dark 



Egg yolk 

 Liver 



20.4 

 28.6 

 23.2 

 23.0 

 22.6 

 23.2 



32 



14 

 22 

 24 

 23 

 23 



