METAMORPHOSIS IN FROG LARVAE 537 



the convolutions in the ovaries of frog larvae appear to be an 

 indication of their development. In figure 10 is shown the gonads 

 of a thyroid-fed larva, which was well along in metamorphosis 

 when killed. These gonads were taken from the animal shown 

 in figure 6. When they are compared with the gonads shown 

 in figure 11 taken from the control animal shown in figure 6 



Fig. 8 Alimentary tract of thyroid-fed larva marked C in figure 7. Length 

 of gut 100 mm. 



it is obvious that the acceleration of body development has had 

 no effect upon the gonads. That the germ cells were unaffected 

 is shown by a comparison of figures 12 and 13. These figures 

 are diagrams of representative transverse sections through the 

 gonads figured in 10 and 11. The germ cells of both thyroid-fed 

 and control larvae are in identical stages of development. In 



