Sex-limitetl iiiiicritanci' iu Lifchnis dioica L. 297 



If tlui fciiialf is ,-1 iicutr.'il homozygote, tlie B I'lictui- miist he foiipled 

 with F, just as if ahc wi'ie a jjositive homozygote, tlie only difference 

 in the formulae being tiiat an M replaces the f in the formulae of the 

 males. Tlie formulation on this basis appears as follows: — 



XBF.XBF homozygous broad-leafed female, 

 XBF.XhF heterozygous l)road-Ieafed female, 

 XBF.XITM broad-leafed male, 

 XbF .XhM narrow-leafed male. 



All three formulations fit the genetic facts and all can be with 

 equal propriety related to a chromosome explanation of sex. Something 

 more is needed before it can be decided tiiat one of these formulae is 

 morelik(dy to be a correct symbolization of the genotypic mechanism 

 of sex in Lychnis, than tiie others, and what is true of Lychnis in tiiis 

 regard, is likewise true of sex-inheritance iu most other species. 



A niiiüber of cases ai'e now known in wliich genetic factors which 

 affect the same character, act in opposite directions, some producing or 

 intensifying a given character which others inhibit, diminish, or modify 

 in other ways. The same end-result may be produced by a retrogressive 

 variation from a more advanced condition, or by a progressive variation 

 from a less advanced condition. This being. the case we are scarcely 

 warranted in assuming that siicii universally distributed differential 

 characters as fenialeness and maleness are produced in all different 

 organisms by the same method, even thougii we can successfully apply 

 to all of them the same set of foruiulae. The fact seems to be that 

 the genotypic nucleus wliich is common to botii the males and females 

 of any species, contains in itself lUMi'ly all of the elements necessary 

 to the production of both the male and the female of that species, and 

 it is tiierefore to a large degree essentially hermaphroditic. This is 

 evidenced by the general occuri'ence in each sex, of vestigial organs 

 which function only in the other sex. Under rare circumstances which 

 are largely or entirely unknown at present, some or all of these vestigial 

 organs may become more highly developed or e\en functional in au 

 individual. The statement often made that the male contains femaleuess 

 and the female contains maleness is based upon such facts as these, 

 but the expression is not particularly approin-iate, since it rests, not 

 u()oii what the two sexes possess, which is distinctive to each, but 

 upon that which they possess in common. There seems no good reason 

 fiM' calling those things which both sexes possess in common, either 

 maleness or femaleness. It must be remembered onl,\ that what they 



Induktive Abstammuiigs- und Vererbungslehre. Xll. 21 



