514 



BENNET M. ALLEN 



Not only is it true that the average volume of the ovaries of 

 the older thyroidless tadpoles is greater than the average of the 

 young metamorphosed controls, but in each individual case this 

 is true. It must be remembered that the thyroidless tadpoles 

 are in an early tadpole stage, in spite of their age and large size, 

 while the controls are completely metamorphosed. 



J:M 



7 S 



Text fig. 7 Ovary of a thyroidless tadpole with 24 mm. body length. Killed 

 February 14. 



Text fig. 8 Ovary of a normal young frog, 48 mm. body length. Killed March 

 13. 



We have seen that there is continued growth and development 

 of the ovary as a whole. There is also marked development of 

 the oocytes. In the thyroidless tadpoles of February 14 and 

 March 6, they are of double the diameter that they exhibit in 

 the recently metamorphosed frogs of July 25. They have be- 

 come quite easily visible to the naked eye. 



