1913] Johnson: Pigment Formation in Amphibian Larvae 61 



Table 1 

 Length measuremeuts and color of tadpoles fed on different amounts of 

 food. Tadpoles of lots A and B were all the same size when the experi- 

 ment began Feb. 10, 1912; those of C and D were the same size 

 when the experiment began, April 28, 1911. Length measurements for 

 lots A and B represent average length of all tadpoles in the dish, those 

 for C and D, the average of several typical tadpoles. 



of 



food 



Full amount 



% full amount 



i/i full amount 



Amount 



of 



food 



Full amount 



% full amount 



i/i full amount 



B. Bana tadpoles fed on eg 

 Length in mm. 



yolk 



Feb. 13 

 15.3 

 15.0 

 15.4 



Feb. 20 

 21.3 

 19.5 

 19.1 



Mar. 6 

 28.1 

 24.4 

 23.2 



Color 

 Light 

 Light 

 Light 



Amount 



of 



food 



Full amount 



% full amount 



Yi full amount 



C. Byla tadpoles fed on liver 



Length in mm. 



May 10 

 16 

 13 

 12 



June 3 

 30 

 23 

 20 



tadpole 

 6 

 6 



Color 

 Dark 

 Dark 

 Dark 



Amount 



of 



food 



Full amount 



% full amount 



y> full amount 



D. Eyla tadpoles fed on egg yolk 



Length i 



Number 



of 

 tadpoles 



Color 



Medium light 

 Medium light 

 Medium light 



Owing to accidents and the small allowance of food, most of 

 the tadpoles living on half the regular fare died before meta- 

 morphosing. I have one preserved .specimen, however, which is 

 about half the normal size and hardly more than skin and bones, 

 but is as deeply pigmented as any of the larger specimens. 



Tornier's experiments with yolk removal were also imitated 

 with the Hyla and Uana tadpoles. Here again it was found that 

 the tadpoles which had lost j'olk, though smaller than the others, 



