18 



INHERITANCE IN RABBITS 



CROSS i. LOP-EARED FEMALE X SHORT-EARED MALE. 



The largest and longest-eared rabbit with which we have experimented 

 was a female obtained by purchase and of unknown ancestry. (See plate i, 

 fig. 2.) Her ear-length was 225 mm. and her adult weight 4,600 grams. 

 She was mated with a small-eared angora rabbit (c? 45, plate i, fig. 3), 

 whose ear-length was 105 mm. and adult weight 3,000 grams. A litter 

 of 8 young was obtained from this pair. All were reared to an age of 

 2 months, when 6 were discarded. The remaining 2 were reared to matu- 

 rity. One of them (^248) is shown in plate i, fig. i. The 6 discarded 

 rabbits had ears shorter than those of the rabbits which were kept. Their 

 ear-lengths are given in table 3 as estimated from the known relation of 

 their ear-lengths at 2 months of age to the ear-lengths of rabbits 247 and 

 248, the animals kept until adult. Table 3 shows that the young obtained 

 from this cross are, as regards ear-length, intermediate between the parents, 

 but stand nearer the short-eared than the long-eared parent. As regards 

 weight, 9 247 is smaller and c? 248 larger than the mid-parental condition; 

 the remaining 6 would probably not have exceeded 9 247 in weight had 

 they been reared to maturity. Accordingly as regards both size and ear- 

 length in this cross the resemblance is greater toward the smaller and 

 shorter-eared parent (father). 



TABLE 3. Cross i. 



Estimated. 



CROSS 2. SHORT-EARED FEMALE x LOP-EARED MALE. 



This cross, the reciprocal to the foregoing, was made repeatedly. The 

 lop-eared male used (rf 179, plate 2, fig. 8) was a son of the lop-eared 

 female employed in cross i. He was, however, smaller than his mother, 

 and had shorter ears. The results of 4 different matings are shown in 

 table 4. In mating i there were only 2 surviving young, which there- 

 fore were probably the largest and strongest individuals in the litter and 

 received more than the average amount of nourishment. One of them 



