62 



INHERITANCE IN RABBITS 



This we might express by adding the Himalayan factor (C) to the for- 

 mula as given for variety 4. Variety 5 is represented in our black X, 

 which when mated with blue c? 1434 (variety 3) produced 4 black and 

 4 blue young. 



Variety 7 is represented in our rabbits 1230 and 1231, 201 1, and 2038; 

 and variety 8, in a modified form, in our d 248, which has sired black, blue, 

 sooty, pale sooty, white, and Himalayan w^hite offspring by black, sooty- 

 yellow, or blue-gray mates. He therefore differs from variety 8 as previ- 

 ously described in that he is heterozygous in the Himalayan factor C 

 His formula accordingly is B2Br2E(R)C'(C)I(D)U2Y2. Some evidence for 

 this classification of our black animals will be found in the table 41. Other 

 evidence is derived from matings with yellow or gray animals. 



Table 41. — Matings of black rabbits with black or sooty individuals. 



BLUE. 



"Blue" pigmentation in rabbits and other rodents is merely a dilute 

 condition of black. The zygotic formula of a blue rabbit is the same as 

 that of a black one, if we substitute D2 for the I2 or 1(D) of the black vari- 

 eties. Blue rabbits may occur theoretically of 8 dift'erent sorts, viz: 



(i) Blue producing blue only; formula, B2Br2E2C2D2U2Y2. 



(2) Blue producing blue, and white; formula, B2Br2E2CD2U2Y2. 



(3) Blue producing blue, and pale sooty; formula, B2Br2E(R)C2D2U2Y2. 



(4) Blue producing blue, pale sooty, and white; formula, B2Br2E(R)CD2U2Y2. 



Table 42. — Matings and young of S 1434, blue. 



Mating. 



With 9647, sooty, variety 2 



Expected 



With $1471, sooty, variety 3 or 4. 



Expected 



With 9 black, variety 5 or 6 



Expected 



Black. 



Blue. 



Sooty. 



Pale 

 sooty. 



