No. 602] SHORTER ARTICLES AND DISCUSSIONS 



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on the grade of the grandparents, but shows i 

 from the mean of the grandparental group (3 



TABLE 143 



All except one of the 8 families classified in table 143 show unmis- 

 takably the reversed regression. This exceptional family consists of 

 the grandchildren of $9747. They have a mean grade of 2.90, sub- 

 stantially the same as that of the entire group of grandparents, but con- 

 siderably lower than that of their own hooded grandmother. Appar- 

 ently she did not come up genetically to her phenotypic grade. This 

 the other grandparents of the group did. For those of lowest grade 

 (2, 2%) produced lower-grade hooded grandchildren than did the 

 grandparents of highest grade (3V2, 4), as was found to be the case also 

 in table 142. 



We may next trace the inheritance of the hooded character through 

 a third but smaller family produced by two successive crosses with wild 

 rats, the hooded character in this case being derived from $6995, 

 grade + 4, generation 12. The character of her first F, descendants is 

 shown in table 141. They consist of 5 hooded and 27 non-hooded 

 individuals. The mean grade of the hooded young is 3.51, but the 

 number of these young is too small to make this mean of much signifi- 

 cance. One of the hooded young ((^9660, +3%) was mated with a 

 wild female to secure a second F, generation and from this in due course 

 was produced the second F, generation (table 144). It consisted of 21 

 hooded and 44 non-hooded young. The hooded young showed the usual 

 range (2 to 4). Their mean grade was 3.50, substantially identical 

 with that of the first F, animals, but 0.25 below that of the actual hooded 

 grandparent. This family history is less satisfactory than the two 

 already discussed because of the smaller numbers which it includes. It 



