GUINEA-PIGS FROM AREQUIPA. 



35 



apparent deficiency of red-eyed young may have been due to our failure 

 at first to distinguish dark-eyed sepias from red-eyed sepias, which look 

 very much alike when first born. In the summary all sepias are treated 

 as dark-eyed unless a specific record in the ledger indicates that they 

 were red-eyed. 



Matings yielding pink-eyed young produced 17 non-pink-eyed and 

 6 pink-eyed young, which is good agreement with the expected 3 to 1 

 ratio. 



BACK-CROSS AND OTHER OFFSPRING OF d" 1002. 



Male 1002 was mated with certain of his F x daughters, producing 90 

 young of 10 different color classes, as indicated in table 21. He was 

 later mated with certain of the female young produced by the matings 

 last described, these females being both his daughters and his grand- 

 daughters and so "f -blood" Arequipa tracing back to himself. (See 



TABLE 21. Classification of young of &1002 by his F\ daughters (table 19). 



table 22.) The table 22 matings have produced to date (April 1915) 

 61 young, distributed in 9 of the 10 classes represented among the table 

 21 young. The classes of young recorded in tables 21 and 22 are the 

 same as those represented among the F 2 young (table 20), with the 

 exception of albinos, which are never produced by d" 1002, since he does 

 not transmit albinism, which is recessive to both of its allelomorphs. 

 As regards the characters in which 6" 1002 is heterozygous, there is 

 evidence from tables 20 to 22 that in the case of each he forms equal 

 numbers of gametes bearing the dominant and the recessive allelo- 

 morphs respectively. By agouti daughters he has had 50 agouti and 

 15 non-agouti young; expected, 49 and 16. By non-agouti daughters 

 he has had 45 agouti and 41 non-agouti young; expected, 43 of each. 

 Combining these totals with those recorded in table 19, we find that 

 in all matings with non-agouti animals he has sired 101 agouti and 

 73 non-agouti young, a not improbable chance deviation from the ex- 

 pected equality of the two classes. 



By red-eyed daughters cf!002 has had 51 dark-eyed and 40 red-eyed 

 young. Adding to this result that recorded in table 19 (last category 



