NON-DISJUNCTION OF SEX CHROMOSOMES 593 



pink females brings out' a new point, namely, that a non-disjunc- 

 tionally produced female manifests her peculiarity directly in Fi 

 by producing more like herself. The two white females pro- 

 duced here came from the union of the two-X egg with the 

 no-X sperm of the vermilion pink male, and should be entirely 

 maternal and entirely non-paternal in sex chromosomal compo- 

 sition, i.e., they should be exact counterparts once more of their 

 mother. Wherefore, if they should be mated to a male like their 

 father, the same story should be repeated. This test was made : 



Pi white pink matroclinous 9 X vermilion pink (outcross) cf 



Fi wHite (pink) 9 pink 9 white (pink)cf verm, pinkcf 



33 25 1 



The culture unfortunately ran out before the point was com- 

 pletely established, but the appearance of the one patroclinous 

 vermilion pink male makes it certain that white pink females 

 would ultimately have appeared. 



The other of these two white pink females (the first was mated 

 to the vermilion pink <f) was mated to an eosin male of an unre- 

 lated stock. The story was repeated, but with a very important 

 modification, namely, that the non-disjunctional males were eosin.. 

 The results were as follows : 



Pi white pink 9 (non-disjunctionally derived) X eosin cf' (pure stock) 



Fi white 9 



(heterozygous white-eosin 



for pink) compound 9 white cf eosin cf 



1 119 101 4 



The results show that the non-disjunctionally derived female 

 produced non-disjunctional females once more, and that like her 

 mother she was homozygous for white (all female offspring white- 

 eosin compound and all normal sons white), and that the sex 

 chromosomal characters of the non-disjunctional sons do not de- 

 pend in any degree upon the composition of their mother but 

 only upon that of their father, in the first case cited, white 

 miniature, here eosin. Moreover, of sister females, one produced 

 vermilion and the other eosin patroclinous sons when mated to 



