THE AMERICAN NATURALIST [Vol. LII 



A few of the characters in respect to which these va- 

 rieties differ significantly might be termed " qualitative. " 

 'These are roughness of the boll surface, color of the 

 fiber and fuzziness of the seed, all of which are included 

 in the lists of allelomorphic pairs of characters in cotton 



given by Balls (1909, p. 18) and by McLendon (1912, pp. 

 168, 169). 7 Yet in the Pima X Gila hybrids these charac- 

 ters behaved like the size and shape characters, showing 

 unimodal distribution in the F 2 . It should be noted, 

 however, that in respect to these characters the differ- 

 ences between the two Egyptian varieties are much 

 smaller than the differences between the parents of the 

 wider crosses (Egyptian X Upland and Sea Island X 

 Upland) dealt with by Balls and McLendon. Instead of 

 the differences between pitted and smooth bolls, buff and 

 white fiber and smooth and fuzzy seeds we have, in com- 

 paring Pima with Gila, merely the differences between 

 more and less numerously and regularly pitted bolls, 

 lighter and darker buff-colored fiber and more and less 

 fuzz on the seeds. 



even in the case of color characters. It is stated, however, by Leake and 

 Prasad (1914, pp. 126-128) that yellow corolla color and the presence of 



