FAMILY HISTORIES 



55 



tests, while the other female, No. 148, made a poor record of 72 sec- 

 onds. It is to 'be noted again that in the seventh generation of this 

 branch of the white family, four of the females made time records 

 inferior to any of those made by the males of the same generation. 

 Another family, mostly of yellow mice, was derived from a yellow 

 female and an unknown male, probably white. The first generation 

 from this mating gave a litter of six, Nos. 32 to 37 inclusive. The 

 records of five of these, one having died, are given in Table IV. and 

 are graphically represented in Fig. 15. This litter gave a family 

 average of 56.6 P.E. 10.1 seconds. Two of the males, Nos. 32 and 

 33, made poor records; No. 34, an average record of 56 seconds; 

 while the remaining male made a fairly good record of 37 seconds. 

 No. 37, the only 'female of this litter, gave a record of 17 seconds; 

 she mated but once, and it is not known with which brother. She 

 bore in the second generation two females and 'a male, Nos. 54, 55 

 and 56. One female, No. 54, made a record of 35 seconds, while the 

 other female made a poor record of 112 seconds. The male, No. 55, 

 also did poorly with an average of 150 seconds. No. 54 and No. 56 



No.lfc7Y Na/68Y N<xlBI. 



/PAAAIy AverAG 



FIG. 16. Descent of a Family of Mice composed of Colored Individuals. 



