540 



W. W. SWINGLE 



the date of feeding, the tails of the thyroid-fed tadpoles were 

 much atrophied and the hind limbs had grown considerably. 

 Twenty-six days from the date of the first administration of 

 thyroid, the fore limbs had broken through the skin; the tadpole 



Fig. 11 Gonad of control for thyroid-fed larvae shown in figure 9. 



mouth had given place to that of the frog. The tails of these 

 animals had suffered considerable atrophy. By May 4 all of 

 the thyroid-fed animals had died. Figure 14 is a photograph of 

 this series of starved larvae and their controls. The controls for 



