146 



W. H. LONGLEY 



/SOf 



1^0- 



150 



120- 



110 



too - 



90 



80 



70 



60- 



50- 



-4-0 



30 



30 



/o - 



B 



Fig. 1 Blocks represent individuals. Shading indicates occurrence of ovula- 

 tion. A, animals all in.seminated; B, none inseminated. Time: (A) hours 

 elapsed after pairing. {B) after first willing to pair. 



