SEX-CHROMOSOMES AND INHERITANCE 193 



autosomes a factor for pale, and if a spermatozoon, carry- 

 ing the factor for pale, fertilizes each nucleus, the two 

 zygotic nuclei will be ZW female and banded, and ZZ 

 male and pale. This gives at least a formal explanation 

 of the results, and helps us to see how such a rare event, 

 the appearance of two gynandromorphs in the same brood, 

 happened to occur at the same time; because, as Doncas- 

 ter^s evidence shows, a double nuclear condition may be 

 characteristic of the eggs of certain females. 



Fig. 90. — Diagram illustrating how a heterozygous egg with two nuclei fertilized by two 

 sperms might produce a gynandromorph like that shown in Fig. b'J. 



' ' Intersexes ' ' and Sex Genes 



The quantitative relation of one X for male and two 

 X's for female that has been found to hold in many of the 

 groups of animals might seem from a purely a priori 

 point of view capable of being modified in such a way that 

 an intermediate condition might be realized, but whether 

 such conditions should be expected to give rise to her- 

 maphrodites or to non-sex-somethings (intermediates) — 

 or to a mosaic of both sexes, or should rather be expected 

 to die could scarcely be foretold. There are three cases 

 in which individuals called ' ^ intersexes ' ' have been found, 

 or produced; and since their interpretation has led to a 

 view that has appeared to contradict the ordinary sex- 

 determination scheme, these cases must be briefly referred 

 to here. Goldschmidt has studied very thoroughly ^ ^ inter- 



13 



