Correlation and Variation in the Toad 583 



through the second decimal place. This holds true for all of the 

 external dimensional characters, namely, length of body, thigh, 

 shank, foot, leg, head, width of mouth and total length. The ratio 

 between weight of gastrocnemii and total weight is the same in 

 both sexes but as related with the other characters the gastrocnemii 

 are much lighter in the male. So too the liver is proportionately 

 lighter in the male with respect to every character except total 

 weight. The alimentary canal is, on the contrary, longer in the 

 male except as compared with total weight, weight of gastrocnemii 

 and liver. The ratio between total weight and other characters 

 is quite inconstant: the males are lighter with respect to total 

 length, length of body, foot, leg, head, and alimentary canal and 

 heavier with respect to length of thigh, shank, width of mouth and 

 weight of liver. 



TABLE III 



Ratios between means of certain characters in the two sexes 

 Ratio between average 



Length of body and total length 



Length of thigh and total length 



Length of shank and total length 



Length of foot and total length 



Length of leg and total length 



Length of head and total length 



Total length and length of alimentary canal 



Length of head and width of mouth 



Total weight and weight of gastrocnemii 



Total weight and weight of liver 



Upon plotting the measurements, examination of the frequency 

 polygons shows that all of the distributions are skew. The 

 exceptionally wide range of the measurements and the relative 

 fewness of observations possible render any exact analysis of these 

 curves unprofitable but one or two general points are to be noted. 

 The curves are of the usual type given by such data (Pearson's 



Type IV) and in nearly all cases the skewness I a = 1 has a nega- 

 tive value, that is the greater number of individuals are below the 

 average with respect to a given character. Table IV gives the 

 means, theoretical modes and indices of skewness of all the char- 

 acters measured. In all of the external characters, including total 



