GUINEA-PIGS FROM AREQUIPA. 



37 



Matings of red-eyed animals inter se have in most cases produced only 

 red-eyed or albino young, but two matings have also produced pink- 

 and-red-eyed young, i. e., animals which are pink-eyed but develop no 

 yellow in then- fur, in which last respect they differ from ordinary 

 pink-eyed and agree with ordinary red-eyed. (See tables 24 and 27.) 



TABLE 23. Young produced by matings of red-eyed males, descended from 

 <?1002, v."ith dark-eyed females of race B. 



Most of the red-eyed animals, when bred inter se, produce albino as 

 well as red-eyed young, showing themselves to be heterozygous for 

 albinism and so of the formula C r C a . This is not surprising when we 

 recall that all the Fj. red-eyed animals must by hypothesis be of this 

 formula, and that two-thirds of the F 2 red-eyed should be of the same 

 sort. In a few matings of red-eyed with red-eyed, which failed to 

 produce albino young (table 24), it is probable that one or both parents 



TABLE 24. Young produced by matings inter se of red-eyed descendants 

 of<?1002. (See also table 27). 



were homozygous for red-eye. Matings of red-eyed with albino animals 

 (table 25), which failed to produce albinos in 6 or more young, afford 

 clear criteria for red-eyed animals free from albinism and so of formula 

 C r C r . Only one mating of a red-eyed animal with an albino has pro- 

 duced pink-eyed young. (See table 27.) The red-eyed parent in this 

 case (cf 48) was mated with 4 other albinos (all of race B) without 

 producing pink-eyed young, but only red-eyed (13) and albinos (17). 

 The female which produced pink-eyed young was his sister, derived like 



