PLATE I 
Fig. 1. Curves illustrating changes in weight during metamorphosis. The 
ordinates indicate weight in grams; the abscissae, stages in development as 
defined in the text. AB, Curve of total weight of Rana pipiens; A'B’, Curve 
of total weight of Ambystoma tigrinwm; AC, Curve of weight of stomach and 
intestine with contents in R. pipiens; A’C’, Curve of weight of stomach and 
intestine with contents in dA. tigrinum; AD, Curve of weight of liver in 
R, pipiens; A’D’, Curve of weight of liver in A, tigrinwm 
Fig. 2. Curves illustrating changes in length of stomach and intestine dur- 
ing metamorphosis. The ordinates indicate length in em. in A. and in mm. 
in B; the abscissae, stages in development as defined in the text. AE, Curve 
of length of stomach and intestine in R. pipiens; A’E’, Curve of length of 
stomach and intestine in 4. tigrinum; AF, Curve of length of stomach in 
R. pipiens; A’F’, Curve of length of stomach in A. tigrinum 
