186 



JOHN S. DEXTER. 



tility are now being investigated. At present, at least, the 

 fact is very apparent, not only in my own results, but also in 

 those published by Morgan. 



TABLE II. 



TABLE SHOWING RESULTS OF EXPERIMENT I. 



EXPERIMENT II. 



In this experiment, the reverse cross was made, viz., pure 

 YW females by pure NR males. According to the theory if no 

 coupling occurred, the FI and F 2 generations should give the 

 results shown by Table III. 



TABLE III. 



Pi. YWXYWX = YW9 



Gametes YWX 



Fi. NRX YWX = NR9 



Gametes (i) NRX, (2) YWX, 

 (3) YRX, (4) NWX 



F 2 . NRX YWX = NR 9 



YWXYWX = YW9 

 YRX YWX = YR9 

 NWX YWX =NW9 



NRXYW = NRtf 

 NRX, YW 



YWXYW = YW<? 

 YWX, YW 



NRXYW = NR<? 



YWXYW = YWtf 



YRX YW = YRtf 



NWX YW = NW<? 



