184 



ROSCOE R. HYDE 



between the truncates and the Woods Hole stock were used. 

 The hybrids came from the cross given in table 6. 



In the experiments given in table 11 the hybrids came from 

 crosses between inbred and truncate stock, as recorded in 

 tables 15a, b, Part I. At this time the inbred stock was in the 

 F5 generation and was a high-producing strain. The truncate 

 stock was in the F48 generation. 



The results of these three experiments make it certain that the 

 hybrid offspring from the low-producing truncates and high pro- 

 ducing wild stocks are high producers. In fact, the hybrids 

 produce equally as weU, if not better, than the high producing 

 parental stock. Moreover, it makes little if any difference 

 whether the father or mother is from the low-producing truncate 

 stock. The following experiments give the evidence that bears 

 on the question as to whether the low rate of fertility of one of the 

 parents will reappear in the F2 generation. 



Tables 12 and 13 give the results of testing in pairs the offspring 

 of the hybrids, derived from the crosses between the low-produc- 

 ing truncates and the high-producing wild stocks. The pairs as 



TABLE 11 



Hybrids of the crosses between the truncate stock and the inbred stock; the Fi gen- 

 eration 

 TABLE 11 a TABLE 11 b 



The Fi generation from truncate Reciprocal: The Fi generation from 



9 X inbred cf truncate d' X inbred 9 



* Died at end of sixteen days 

 because of failure to feed on transfer 

 to new bottle. 



