38 T. H. MORGAN AND ELETH CATTELL 



The linkage of RY and WB 



In order to obtain a larger amount of data for linkage of R 

 and Y versus W and B, when the result is not complicated by 

 other factors, we repeated one of our former crosses that was 

 too small for the matter in hand. Long, red, yellow females 

 were crossed with long, white, black males and gave LRN 9 and 

 LEY d". The numerical results for Fi and F2 are given below. 



LRY 9 LWB c? 



LRN 9 = 622 

 ^' LRY d^ = 521 



LRN and Bl 9 2034 

 LRY and Br 9 1740 

 LRY and Br d" 1682 

 LWN and Bl ^ 1561 



LRN and Bl d^ 43 

 LWY and Br ^ 10 



In the total of 3243 males there were 53 cases of cross-over 

 or 1:61. In the former experiment there were 260 males and 

 no cross-overs. 



In order to obtain still more data some of the Fi LRN 9 of 

 the last cross were mated with the double recessive LWY cf . 

 Since the latter contains both of the recessive factors, w and b, 

 all the offspring of the cross, both males and females, may be 

 counted. The results were as follows: 



LWN c? and 9 = 2731 



LRY c? and 9 = 2923 



LRN cf and 9 = 43 



LWY c? and. 9 = 34 



In a total of 5644 there were 77 cross-overs or 1 to 73.3. 



