No. 611] FERTILITY IN SOUTHDOWN SHEEP 677 



L.6615±. 00737 

 1.7177±. 01239 

 L. 7381 ±.06034 



The difference between singles and twins is .0562 

 + .01435; between singles and triplets is .0766 + .06079; 

 and between twins and triplets is .0204 + .06159. The 

 only significant difference is between singles and twins, 

 which is 3.88 times the probable error. 



The probable errors involved seem to indicate little, 

 hence a comparison by correlation of the maternal grand- 

 sire and progeny, and maternal grandam and progeny 

 was instituted. Table XXI presents the correlation for 

 the maternal grandsire, Table XXII for the maternal 

 grandam. 



TABLE XXI 



The coefficient of correlation for Table XXI is .0496 

 + .0118, while for Table XXII it is .0382 + .0118. The 

 difference between the correlations of maternal grandsire 



