GENERAL LIFE HISTORY OF THE TADPOLES 



37 



reaching 1,193 mg. There were large fluctuations in the size of suc- 

 cessive collections at the same place, and it is likely that, in this pond as 



10 20 30 

 APRIL 



o 20 30 



MAY 



9 19 29 



JUNE 



9 19 29 8 



JULY AUG, 



Fig. 12. Hospital Pond, 1949 



The same pond, observed throughout the season. The graph shows good 



growth, no great contrasts in the weights between the colonies, except on 



one date, and late metamorphosis. 



in the others, there were nomadic colonies of tadpoles, some of which 

 fared much better than others. 



From these examples of ponds that were either known to have 

 nurtured metamorphosed frogs, or at least probably did so, I turn to 

 two others. In both, disaster overtook all the tadpoles. In one, an 

 interesting colony was studied as a natural process of extinction took 

 place. 



