RELATION OF GLANDS TO IODINE AND METAMORPHOSIS. 413 



were found. In Table VI. the hind leg lengths of pituitary- 

 thyroidless tadpoles normally fed and killed more than a month 



TABLE VI. 



Rana pipiens WITH PITUITARY AND THYROID GLANDS REMOVED. 



later than the above are found to be in sharp contrast to these. 

 None of these pituitary-thyroidless Rana pipiens tadpoles were 

 brought to metamorphosis by iodine feeding but there is little 

 doubt but that it will be possible to do so; at any rate there is 

 an extremely strong tendency in that direction. 



TABLE VII. 



SIZE OF THYROID GLANDS AND COLLOID MASSES OF PITUITARYLESS Bufo TAD- 

 POLES IODINE FED. NUMBERS OF SPECIMENS CORRESPOND 

 TO THOSE OF TABLES I. AND II. 



Dimensions of Thyroid Gland. 



The iodine-fed pituitaryle.ss Bufo tadpoles shown in tables 

 I. and II. were sectioned and their thyroid glands studied, with 

 the object of seeing whether the iodine feeding had brought about 



