TEMPERATURE AND EMBRYONIC DEVELOPMENT 



137 



The temperature tolerance of the Urodele eggs is generally at a lower range than for the 

 Anuran eggs. Further, development at lower temperatures will be retarded for any em- 

 bryos, within limits of viability. Record the data as follows: 



DATA FOR SPECIES- 



STAGE (50% of eggs) at HOURS AFTER FIRST CLEAVAGE* 



DATA FOR SPECIES. 



STAGE (50% of eggs) at HOURS AFTER FIRST CLEAVAGE=: 



DATA FOR SPECIES. 



STAGE (50% of eggs) at HOURS AFTER FIRST CLEAVAGE* 



* Note: The final graph should be corrected by adding the time between insemination and placing the eggs at the various ten 

 peratures (2-1/2 hours or more). 



