20 



INHERITANCE IN RABBITS 



On the whole, the result of cross 2 is a fairly close approximation to 

 the mid-parental ear-length. In no case does the deviation from the mid- 

 parental value exceed 11 mm.; the average deviation from it is only 4.8 

 mm. But the differences between the respective parents ranged from 100 

 to 118 mm., and the least deviation of one of the offspring from either 

 parent was 45 mm. or more than four times the greatest deviation from 

 the mid-parental value. When deviation from the mid-parental value 

 did occur, it was oftener under than over the mid-parental value. 



Accordingly, the results observed as regards ear-length may accurately 

 be described as a blend. As regards body-size, the data are insufficient, 

 since adult weights of the offspring were in no case obtained, but the 

 observed weights of the offspring in matings i and 2 indicate that a blend 

 might be expected, an intermediate condition having already been obtained 

 at 20 weeks of age. 



Cross 3. — Belgian Hare Female X Lop-eared Male. 



The "Belgian hare" (plate 3, fig. 9) used in this cross was larger and 

 had somewhat longer ears than the short-eared rabbits used in crosses i 

 and 2. The lop-eared male was father of the one used in cross 2, but had 

 about the same ear-length and body-size. A Htter of 6 young was ob- 

 tained, five of which were reared to an age of 21 weeks or more. In size 

 the offspring exceeded either parent, approximating that of the female 

 lop used in cross i. Four of the 5 young also exceeded the mid-parental 

 ear-length by from 2 to 6 mm., but the fifth fell short of it by 8 mm. This 

 same individual (diyj) showed the least deviation from either parental 

 ear-length, viz, 38 mm., or four and a half times the greatest deviation 

 from the mid-parental ear-length. 



Accordingly, in cross 3, as in cross 2, the ear-length of the offspring is 

 approximately a blend of the ear-lengths of the respective parents. The 

 size of the offspring, however, is greater than that of either parent, though 

 it does not exceed the size of lop-eared individuals other than the father. 



