560 
Journal of Agricultural Research voi. xxm, no. 7 
not used subsequently, all of them, so far as could be observed, possessed 
perfectly erect ears, which, however, were slightly larger than on Berk- 
shires of equal size. 
Although the F 2 generation consisted of 151 individuals, only 42 had 
become mature enough to determine definitely the shape of ear when the 
work was discontinued. Of these only one (PI. 1, F) showed a typical 
Duroc-Jersey ear; several showed shapes intermediate in various degrees, 
and the great majority showed typically erect Berkshire ears. 
The Duroc-Jersey sow that was the dam of all the F x generation which 
was saved for breeding purposes was mated to an F t son from her first 
litter (PI. 1, E). There resulted three litters totaling 35 pigs, most of 
which died young or were still young when the experiment was discon¬ 
tinued. Of the 9 which were 6 months old or more at that time, 4 had 
typical Duroc-Jersey ears, 1 was still undetermined, and 4 had ears com¬ 
pletely or almost completely erect. 
The following conclusions in regard to the inheritance of the set of ears 
are warranted by the data: The typical erect ear of the Berkshire is 
dominant by at least one and probably not more than three (F 2 ratio of 
41 erect or intermediate to 1 of Duroc type) principal factors. There are 
probably a number of minor modifying factors for size and quality as well 
as for the amount of breaking over. Neither breed is homozygous 
throughout for all the factors concerned in the production of its own 
peculiar ear shape—that is, being pure-bred is not equivalent to being 
homozygous in this respect. 
inheritance of shape of face' 
This character, like the shape of ear, does not complete its develop¬ 
ment until the animal is mature and is fairly constant within each of 
the breeds of swine. 
Both the Tamworth and the wild hog are characterized by long, 
narrow, straight faces with almost no forehead prominence. The face 
of the wild hog is the more extreme in each of these respects, and the 
seven mature F x pigs all approached very closely to the face shape of 
their wild parent. 
Among the common American breeds of hogs, the Berkshire repre¬ 
sents the brachycephalic opposite to the wild hog in face shape, having 
a very short, extremely dished face and a forehead so broad and promi¬ 
nent as to give it a sort of pompadour appearance (PI. 1, G). The 
facial angle, while varying somewhat like any other quantitative char¬ 
acter, is fairly constant and approximates a right angle. Only two F t 
pigs from the wild X Berkshire cross matured, and both resembled the 
wild parent so closely that, except for color and wider foreheads, they 
would have been indistinguishable from the F/s of the wild X Tam¬ 
worth cross. One of them, however, also had a slightly shorter face 
than either his litter mate or the F/s wild X Tamworth. Not enough 
data are available to indicate whether or not this was due to some 
variation in development. 
Seven of the 10 pigs composing the Fj generation of the Berkshire 
X Tamworth cross matured, and none of them could be distinguished 
from pure-bred Tamworths as far as face shape was concerned. This is 
especially surprising because Simpson {16), who crossed Yorkshires and 
Tamworths, reported that the Yorkshire face (which is quite similar in 
appearance in respect to dish of-face to the Berkshire, though longer) 
