62 



CHARLES A. COBURN 



As is seen here 9 429 came from a 9 W-N X cf T-N mating, 

 cf 438 from a 9 W-N X d' W-S mating, and 9 351 from a 

 9 W-S X cf W-S mating. From the mating of 9 429 (W-N) 

 with cf 438 (W-N) there were 2 w-n and 1 t-n mice, while from 

 the mating of 9 351 (T-N) with cf 438 (W-N) all the five 

 mice were w-s. From the blending type of inheritance alone 

 we would be led to expect a higher grading from the former 



P2b 



F3b 



W-S 



? 



I 

 225 



T-N 

 <? 



504 



W-8 "-8 



Fib 2<ri« 



677 

 I 



1 Litter 

 ' — v=s- 



5<? 



1 Litter 



I ^ 



w-8 W-n t-8 



2<? 



tr=n 

 679 



w-8 



4<?g2 



I I 



i26 629 



M 



5 Litters 



5 Litters 



I , 



w-n x-e 



2$ 



Tin— 

 26 1$ 7<? 1? 



)?. 



395 39A(IJied before 



tested) 



42^- 



2^ 2(? 12 



t-B 





1 Litter 



2(?' 12 

 (Died before 



tested) 



w-8 w-n 



3d" 



(1 died after let. teat) 



Chart 3. 



t-n 



mating than from the latter since both parents of the former 

 were W-N, while the female in the latter was a T-N. To find 

 a possible explanation we must go back to the preceding gen- 

 eration. Here we find in the case of the former mating an 

 ancestry consisting of two female W-N, one male T-N and the 

 other W-S, while in the case of the latter mating one female 

 of the preceding generation was a W-N and the other female, 

 and the two males were each W-S. Other cases are to be found 



