PLATE 2 



EXPLANATION OF FIGURES 



R. sylvatica. All natural size. Drawn in 70 per cent alcohol. 



10 and 11 Thyroidless. 4/28/17 to 7/10/18. Alive: Tot., 72mm., B., 25 mm.; 

 fixed: Tot., 69 mm., B., 25 mm. 



12 and 13 Control. 4/14 to 5/29/18. Alive: Tot., 47 mm., B., 18.5 mm.; 

 fixed: Tot., 43 mm., B., 18 mm. 



14 and 15 Thyroidless. 4/14 to 5/28/18. Alive: Tot., 50 mm., B., 19 mm.; 

 fixed: Tot., 46 mm., B., 18 mm. 



16 and 17 Control. 4/14 to 6/1/18. Alive: B., 15 mm.; fixed. B., 14 mm.; 



18 and 19 Thyroidless. 4/14 to 7/13/18. Alive: Tot., 65 mm., B., 25 mm.; 

 fixed : Tot., 60 mm., B., 23 mm. 



20 Precocious frog with regenerated thyroid. 4/11 to 7/10/17. Alive: B., 

 10.5 mm.; fixed: B., 8 mm. 



21 Control. 4/11 to 7/10/17. Alive: Tot., 40 mm., B., 15.5mm.; fixed: Tot., 

 37 mm., B., 14 mm. 



The dates given refer to the beginning of the experiment and the date of 

 killing the animal, thus indicating the age of each specimen. In stating the 

 length. Tot. = total length; B., = nose-anus length. These specimens were 

 selected as typical of the different groups. For the full number see table 1. 



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