EAR-SIZE 



25 



fested. The young vary in normal fashion about a mean ear-length of 

 130.4 mm. The total range i.s only 13 mm., indicating no Mendclian 

 heterogeneity among the gametes [produced by the jjarents, though both 

 were Fj half-lops. 



One of the young produced in this Utter (9400) was mated with the 

 lop-eared cfiyg, table 2. The result is shown in table 12. Six offspring 

 were obtained from this mating; they vary rather closely about the mid- 

 parental ear-length, though chiefly below it, as we might e.xpect from the 

 fact that the mid-parental value given is based upon measurements of 

 adults, and that of the young upon measurements at the age of 20 weeks. 

 The total range of variation is 15 mm. 



Female 400 was hkewise mated with her father (d"248), producing a 

 litter of 4 young, all of which fell below the mid-parental ear-lengths. 

 (See table 13.) 



Table 13. 



The deviations are —9, —7, —16, and —18, average —12.5 mm. But 

 the total range of variation is only 11 mm., or scarcely greater than that 

 observed among short-eared rabbits. Certainly tliis result affords no 

 evidence of heterogeneity as regards ear-character among the gametes 

 formed by the parents, though one was an Fj and the other an Fj cross- 

 bred between the lop-eared and the short-eared races. 



