Ill] 



ITS PERIODIC RETARDATION 



85 



While as a general rule, the better the animals be fed the 

 quicker they grow and the sooner they metamorphose, Barfiirth 

 has pointed out the curious fact that a short spell of starvation, 

 just before metamorphosis is due, appears to hasten the change. 



60 70 80 90 

 days 



10 20 30 40 50 



Fig. 14. Growth in weight of Tadpole. (From Ostwald, after Schaper.) 



The negative growth, or actual loss of bulk and weight which 

 often, and perhaps always, accompanies metamorphosis, is well 

 shewn in the case of the eel*. The contrast of size is great between 



* Joh. Schmidt, Contributions to the Life-history of the Eel, Rapports du Conseil 

 Intern, pour V exploration de la Mer, vol. v, pp. 137-274, Copenhague, 1906. 



