IN THE SECOND CHROMOSOME. 



313 



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

 the original Nova Scotia chromosome contained two factors: 



On i, located to the left of purple, 1 which makes star black 0.0, 



and reduces black-purple. 



C n r , located between purple and speck, 1 which greatly reduces 

 the whole purple speck region. 



RIGHT-HAND END OF NOVA SCOTIA CHROMOSOME (C//,). 



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



C C 



some and a black curved speck chromosome , mated to 



o c s p 



a black curved speck male. It is included in tables 1 and 5. A 

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



end of the Nova Scotia chromosome, but not the left ( ) 



\o c Sp/ 



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

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



speck. A wild-type daughter, r , was mated to stock black 



c s p 



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

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



C 



II r 



daughter, 7 ~ , was mated, in culture 318, to stock black 

 ' o p r c' 



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 was tested. 

 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 black 

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



1 Tests made more recently, in connection with studies of Cm, n (see below), indicate that 

 Cm is probably to the left of black, and that Cur is certainly to the left of plexus. 



