672 



THE AMERICAN NATURALIST [Vol. LI 



1.2864*. 00593 

 1. 2776 db .01031 



The difference between the breeding performance of 

 the singles and twins is 0.0088 + 0.0119, which is, of 

 course, not sufl&cient to be significant. It indicates either 

 that the male has no influence on the number at a birth 

 (the most probable supposition) or that singles and twins 

 in the males are genetically similar. The difference be- 

 tween the breeding performance of the triplets and singles 

 is 0.1024 + .0777 and between the triplets and twins is 

 0.1112 + .07818, neither of which is significant. 



For the ewes the result is not particularly different. 

 Table XI presents the result of this comparison. 



TA3LE XI 



Tlie <liHVi cn.'c iH'tuccn tlic pmo(^iiy of ewe>^ born singly 

 and tho-e born twin^ i^ .01 ;U9 + 0.109,1 ; between singles 

 and triplets is .05338 + 0.06252 ; and between twins and 

 triplets is .03989 + 0.0655. 



