54 Genetic Studies in Poultry 



Schwierigkeiten, die diese Tatsachen eincr einfachen Losung cntgegen- 

 setzen, noch nicht bchoben sind, und dass noch manche Experimente 

 notig sind." 



Note on the sex-projiortions and ratio of lienny to normal cocks. 



Bearing in mind the irregular sex -proportions that frequently occur 

 where intersexes are found in animals, we thought it worth while to 

 examine our figures from this point of view. In attempting to ascertain 

 whether families with a marked preponderance of either sex shewed a 

 preponderance among the cocks of either normal or henny feathered, 

 we have divided our families into three gi'oups, viz. (a) those with 

 marked excess of $ $, (b) those with marked excess of (/</, and (c) those 

 in which the proportions of the sexes approach equality (cf Table II, 

 p. 56). Our standard of "marked excess" must naturally be an arbitrary 

 one, and in practice we have classified families in which three-fifths or 

 more of the total belong to a given sex as shewing a marked excess of 

 that sex. Thus a family with 20 (/</ and 11 $ $ is regarded as shewing 

 a marked excess of cTc/" J a family with 7 cfc/ ^^'^^ 12 $ $ as shewing a 

 marked excess of $ $ ; while a family with 12 </£/• and 9 $ $ is classified 

 as one shewing approximate equality. The classification is of course 

 quite rough, and we do not suggest that any special significance should 

 be attached to the resultant groups. In classifying the families, we have 

 kept those in which the henny character came from the mother distinct 

 from those in which it was transmitted by the father. We should add 

 that the sexes were in most cases only recorded in the live birds as they 

 gi'ew up. In relatively few cases was the sex determined by dissection 

 of a chick that had died early. The results of our grouping are given in 

 Table II, p. 56. It will be noticed that, where the henny character is 

 transmitted by the father, the proportion of normals and hennies among 

 the sons is nearly equal in each of the three groups. This is also true 

 for cases where it is transmitted by the mother, in the group where the 

 sexes are approximately equal, and in that in which there is an excess 

 of females. But where there is an excess of males in the offspring, the 

 normal sons are nearly twice as numerous as the hennies. Moreover 

 this excess of normals is found in all of the seven families concerned 

 except one (Exp. 41), in which the numbers are very small. The figures 

 as they stand suggest something more than chance distribution, and 

 further experiments have been planned to test the point. 



