PLATE 8 



EXPLANATION OF FIGURES 



R. sylvatica. Ovaries, X 36 



94 Half-grown normal larva (fig 21). Oocytes, 50 n. 



95 Precocious frog (fig. 20). Oocytes, 75 /x. 



96 Young normal frog (1917). Oocytes, 120 yu. 



97 Young thyroidless larva (1918). Large as control larva at metamor- 

 phosis. Oocytes, 50 n (smaller oocytes than those of 1917 larvae of same size). 



98 Thyroidless larva (1918) (5 weeks old). Much younger than that of 

 figure 97, but of much larger size, oocytes (60 n) are relatively of the same size. 



99 Thyroidless larva one-half the size of larva of figure 98, but more than 

 twice as old (eleven weeks) Oocytes (130 /i) are relatively about four times as 

 large in diameter as those in figure 98. 



100 Thyroidless larva (1918). Very little older than larva of figure 99 (twelve 

 weeks), but nearly four times as large. Oocytes (180 /x) are relatively smaller 

 than those of figure 99. 



101 Thyroidless larva (6 months old), killed in October, 1917. Oocytes, 

 200 M. 



102 Thyroidless larva killed December 21, 1917 (eight months old). Oocytes, 

 250 m. 



103 Thyroidless larva fifteen months after thyroidectomy. Oocytes, 300 ix. 

 Measurements rejiresent the diameter of the largest oocytes. 



66 



