94 SEX INHERITANCE 



tion of F and M may be in hermaphroditic types, it is 

 less inconsistent to use the symbols for the sex chro- 

 mosomes as the symbols for the sex factors also, if 

 it is at the same time recognized that the whole 

 chromosome is not involved in determining sex. 



The same factors that determine whether eggs or 

 sperm develop in an individual must also be respon- 

 sible for the development of many characters that go 

 along with the male or the female condition, in other 

 words those characters that are different in the two 

 sexes (sex limited). Sex factors of whatever kind, 

 however, must like all factors be supposed to produce 

 their effects in conjunction with the rest of the cell, 

 with other factors, or w r ith anything else there, for it 

 must always be remembered that the sex factor is 

 only one of many factors that are at work. Hence 

 for the realization of any particular character that is 

 associated with a particular sex there are probably 

 many factors that cooperate. If the latter change, 

 the character in question may also change, while the 

 sex factor remains the same. The character may, 

 in this case, be said to be dependent not only on the 

 sex factor, but also .on another differentiator that 

 can only realize itself conjointly with the sex factor. 

 Thus while the accessory sexual organs, as well as the 

 secondary sexual characters and all other sex-limited 

 characters, may be modified by special differentiators 

 that are not present in the sex chromosomes, yet 

 the sex factor also produces an effect on their de- 

 velopment which is different according to whether 

 the sex factor exists in single or double amount. In 



