554 THE AMERICAN NATURALIST [Vol. LI 



Maid 211032, and Imp. White Queen 545726. The pedi- 

 grees of these animals follow in Tables VI and VII. The 

 problem before us is to measure and express numerically 

 the degree of relationship or kinship between these two 

 animals. 



TABLE VI 

 Pedigeee of Imp, Milk Maid (211032) 



g S "H INo. 9: No. 425402 



; a ' \ Balmoral Pearl 



i Lady Balmoral ; 



^ , ^ r Lady Bene dic f.s Farewe ll 



We see that in these two pedigrees there is, in the first 

 ancestral generation, one ancestor (Ireby Signet) which 

 occurs in both. Hence we have 



In the second generation there are three ancestors 

 (Morning Sun, Tulip 28th and Border Stamp), which 

 occur in both pedigrees, whence it follows that 



In the third generation there are six common ancestors 



