602 



Wm. E. Kellicott 



rized by Pearl ('05) : it will be noted that these coefficients are con- 

 siderably lower than those of the older series by the authors just 

 mentioned, and should be used in place of them. The coefficients 

 of variability of all of these organs are given in Table XX. 



TABLE XX 



Coefficients of variahiUty of internal characters 



Human — 



Weight of spleen (Greenwood) 



Weight of heart (Greenwood) 



Weight of kidney (Greenwood) 



Weight of Hver (Greenwood) 



Weight of heart (Reid and Peacock [Pearson]) 



Weight of liver (Reid and Peacock [Pearson]) 



Weight of kidney (Reid and Peacock [Pearson]) 



Capacity of lungs (breathing capacity) (Galton [Pearson]) 



Weight of brain (Reid and Peacock, Clendinning, Sims, Bis- 

 choff, Pearson) 



c? 



Weightof brain (Pearl) 7-59 tf> 



Swine 



Number of Miillerian glands (Davenport and BuUard). 



48.0 



Toad- 



Weight of gastrocnemii 



Weight of liver 



Weight of ovaries 



Length of alimentary canal . 



24.50 

 33-34 



9.81 



28.94 

 35-55 

 53-23 

 12-34 



The great mass of data on variability is drawn from measure- 

 ments of body-weight, stature, skull and other skeletal charac- 

 ters of similar nature. Of these, excluding body-weight as a com- 

 posite of both external and internal characters, the coefficients 

 range from 5.57 to 3.15, an average of 48 different characters in 

 both sexes giving 4.2. In other vertebrates we have essentially 

 similar magnitudes ranging from 8.80 to 2.69. (Lonnberg ('93) 

 gives body-lengths of 14T specimens of Petromyzon fluviatilis 

 which upon calculation show a coefficient of 9.66.) 



Obviously there is an enormous difference in the variability of 

 these external and internal' characters. In the toad we have 



* The use of the convenient words "external'' and "internal'' to distinguish these two classes of char- 

 acters is perhaps justifiable though not exact. As external we may include characters such as stature, 

 length of limbs or limb bones, number of vertebrae, indices and other skull measurements except per- 

 haps capacity, the position, number or size of external parts, etc.; in general all such characters as func- 



