ON HEREDITY IN BABBITS. 293 



individual matings were as follows. N = normal, A = Albino. 

 No. 47 is a Silver Fawn ; Nos. 51 and 52 are Dutch. ; Nos. 1, 

 4, 13, and 25 are Belgians ; and Nos. 2, 3. 6, 23, and 50 are 

 Angoras. 



Table 10. 



Normal x Albino (Fj. 



Matings. Normnl. Albino. 



N 1 X A 2 26 



A3 xN4 16 



A3 x N 51 11 



A6 X N4 8 



N13xA2 4 



A 23 X N 25 16 



A 50 X N 47 8 



N 52 X A 2 5 



Total 94 



(b) Second Generation (F.,). 



The normal hybrids of the first generation bred together pro- 

 duced a mixture of normals and albinos in Mendelian proportions. 

 7 normal hybrids bred together produced 171 young, of which 132 

 were normal and 39 were albinos. The Mendelian expectation 

 for 172 young is 129 normals and 43 albinos. 



Each individual hybrid that was tested produced both normals 

 and albinos, usually in the same litter. The individual results 

 were as follows : — No. 5 gave 13 normals and 4 albinos ; No. 7, 

 22 N and 9 A ; No. 8, 28 N and 4 A ; No. 9, 43 N and 14 A; 

 No. 10, 92 N and 24 A ; No. 11, 26 N and 8 A ; and No. 12, 

 40 N and 15 A. 



It will be observed that No. 8 gives a decided deficiency of 

 albinos, while, as will be seen later, the same individual in a 

 previous litter gave an unexpected excess of albinos when mated 

 with an albino. 



The albinos of the second generation extracted from the normal 

 hybrids of the first generation had apparently the same albinic 

 characters as the original albino grand-parents, viz., a clear skin 

 devoid of pigment, pure white coat, pink eyes, and the swaying 

 habit. 



The normals of the second generation had apparently the same 

 normal characters as the original normal grand-parents and the 



