Nos. 618-619] INHERITANCE IN PEROMYSCUS 295 



TABLE VI 





















Father-daughter 



+0.36 

 +0.24 

 +0.64 





+0.11 



+0.51 



+0.36 

 + ()'.-,! 



+0.23 

 +|»'-^ 



+0.26 

 +0.17 

 +0.26 



+ 0.302. The average of four figures given by Pearson 20 

 (father-son, father-daughter, etc.) for the heredity of 

 stature in man is + 0.335. There is thus found, in these 

 mice, approximately the same degree of resemblance be- 

 tween parents and offspring, in respect to these two char- 

 acters, as is found to occur in man in respect to stature. 21 

 Since the heritability of these individual differences 

 has been proven by means of correlation coefficients, the 

 practicability of selection experiments with such charac- 

 ters i> evident, provided that sufficient numbers of normal 

 animals can be reared. Experiments of this nature have 

 already been commenced by Mr. H. H. Collins and myself. 

 The characters chosen for these tests are coat color, tail 

 length and width of tail stripe. 



VI. Hybridization 



Successful hybrid matings have been made (1) between 

 the Berkeley and the Victorville mice, (2) between the 

 Eureka and the La Jolla mice, and (3) between the Eu- 

 reka and the Victorville mice. 



In the first case, moderate numbers of F x and F 2 ani- 

 mals were reared. In respect to coat color, the 25 F t in- 

 dividuals, when adult, ranged from a condition similar to 

 that of an average Berkeley gambeli to a condition as pale 

 and as yellow as that of the average sonoriensis. More- 

 over, there was here no marked tendency for the mean or 

 intermediate condition to preponderate numerically over 

 the extremes. 



