412 



BENNET M. ALLEN. 



indicated in Table III. The numbers of the points apply to the 

 same individuals shown in the table. The arrow lines connect 

 up points showing the dimensions of each specimen at the be- 

 ginning and at the end of the feeding. 



TABLE IV. 



Bufo PlTUITARY-THYROIDLESS TADPOLES. 



Table V. shows the results of feeding iodine to Rana pipiens 

 tadpoles from which both the thyroid and pituitary glands had 

 been removed. The experiment was begun with five specimens, 

 two of which were not preserved. These five tadpoles at the 

 beginning of iodine feeding had body lengths ranging from 10.3 

 mm. to 15.2 mm. and the hind legs ranged in length from .28 mm. 

 in the smallest to .80 mm. in the largest. It is probable that 

 no. i in Table V. represents the largest and no. 3, the smallest 

 but it is not possible to be certain upon this point because the 

 tadpoles were all kept together in the same aquarium. In any 

 case, the growth of the hind legs is remarkable and it will be 



TABLE V. 



Rana pipiens WITH PITUITARY AND THYROID GLANDS REMOVED. 

 Fed Iodine from June 30 to July 25. 



noted that the left fore limb has appeared in nos. 2 and 3. The 

 heads of these three tadpoles were sectioned and the series care- 

 fully studied in order to detect any remnants ever so small of 

 thyroid or pituitary glands. Not the slightest vestiges of these 



