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THE AMERICAN NATURALIST [Vol. XLVIII 



Z f> {K,) = (0) 



Z 1 (tf,)=25 (0) 



Z, (IT.) =25.00 (50.00) 



Z,(JT 4 ) =37.50 (62.50) 



Z, (A 5 ) =50.00 (75.00) 



Z 5 (A 6 ) =71.88 (87.50) 



Z (A 7 ) =81.25 (92.19) 



Z T (K t ) =90.63 (92.97) 



Z s (A 9 ) =92.77 (93.75) 



Z fl (A 10 ) =93.65 (93.75) 



Z I0 (K n ) =93.85 (93.75) 



The physical meaning of these expressions is simple 

 and straightforward. Z 4 (K 5 ) tells us that in the 5th an- 

 cestral generation of King Melia Rioter 14th he had only 

 one half as many different ancestors as was possible for 

 that generation, and of his ancestors three fourths were 

 common to Iris sire and his dam. However one looks at 

 the matter there can be no denial that King Melia Eioter 

 14th is a closely inbred animal. 



In Fig. 1 the heavy broken line gives the relationship 

 coefficients for King Melia Rioter 14th. Tt will be instruct- 

 ive now to consider another example by way of contrast. 

 Again a Jersey bull, Blossom's Glorene (102701), will be 

 taken. Only the final result need be given. 



The total inbreeding and tlie relationship curves are 



