226 



THE EFFECT OF TEMPERATURE 



stage of disappearance of the yolk plug was determined, 

 these being the most sharply marked periods. The 

 temperatures varied between 4 and 26 C., several ob- 

 servations being made at each temperature, and means 

 taken. 



From the above table we may gather that at the 



24232r2r20 19 18 1716 15H 13 12iri<r9 s 7 g 5 



. 22. Effect of temperature on growth of tadpole. 



highest temperatures employed the rate of develop- 

 ment was respectively 7.2 and 21.9 times more rapid 

 than at the lowest. 



In the accompanying figure are reproduced the re- 



