IN THE SECOND CHROMOSOME. 



313 



black-purple gave a greatly redaced value. It therefore follows that 

 the original Nova Scotia chromosome contained two factors: 



Cn I, located to the left of purple/ which makes star black 0.0, 



and reduces black-purple. 

 Ciir, located between purple and speck/ which greatly reduces 

 the whole purple speck region. 



RIGHT-HAND END OF NOVA SCOTIA CHROMOSOME {Cu ,). 

 Culture 171 contained a female with an original Nova Scotia chromo- 



some and a black curved speck chromosome "^ '^\ mated to 



b c s„ 

 8l black curved speck male. It is included in tables 1 and .'). A 

 black female, produced by crossing-over, must have had the right 



end of the Nova Scotia chromosome, but not the left (- — "' ] 



\h c sj 

 This female, in culture 226, was mated to stock curved speck males, 

 and produced 146 offspring without a cross-over between curved and 



h C 



speck. A wild-type daughter, ^ , was mated to stock blark 



c Sp 



purple curved males (culture 277).. Among 105 offspring, 3 were 



cross-overs between black and curved. One of the three, a wild-type 



^ II r 



daughter, r , was mated, in culture 318, to stock black 



purple curved males. Wild-type daughters, of the same constitu- 

 tion, were again mated to black purple curved males in cultures 354 

 and 355. The results were as shown in table 8. 



Table 8. 



A number of other cultures (see table 9) were made in which this 

 same right-hand end of the Nova Scotia chromosome wa.^^ te^t<-d. 

 All were descended from 226, 277, and 318. The results are included 

 in tables 10 and 11. All these cultures agreed in showing that for 

 the purple-to-speck region we have a result not very different from 

 that given by the whole Nova Scotia chromosome; but for the bUick 

 purple region the result is not very different from the usual one. 



' Tests made more recently, in connection with studies of Cm, it («ec l)elow). indicat« th*t 

 Cui ia probably to the left of black, and that C//r is certainly to the left of plexu«. 



