ON THE INHERITANCE OF AN AURAL ABNORMALITY IN THE AYRSHIRE. 169 
abnormal sire No. 39 with a normal pure-bred Holstein-Friesian cow No. 41, 
whose origin could never be taken for heterozygous with respect to the aural 
peculiarity, has given an abnormal heifer No. 60. There are, therefore, in- 
disputable evidences of dominance of this aural characteristic. 
I have already mentioned that this peculiarity of the nicked ears is very 
different in degree. As far as my collection is concerned, sure cases of the 
first type were found in the bulls "Express", No. 25 and No. 39 and in the 
cows No. 61, No. 62, and No. 67. That the bull "Express" had well-nicked 
ears was stated to me by Mr. Takenouchi, who kept this bull for seven years. 
In five other animals it was ascertained by myself, as they are still alive at 
the present time. Further information from Mr. Takenouchi shows that all 
the offspring from "Express" were calved with nicked ears. This proves 
this bull to have been homozygous in regard to the aural abnormality. It 
appears that the other five animals, above mentioned, might also be homo- 
zygotes, considering that they descended from abnormal parents and moreover 
that no normal ofspring from them has so far been detected. These data lead 
one to conclude that the well-nicked type is pure dominant (DD). 
Turning to the second type, i. e. those which were calved with slightly 
nicked ears, we see in the genealogical table that all animals belonging to this 
type are the progeny coming from parents, one of whom is abnormal, the 
other normal. In other words, the individuals with slightly-nicked ears 
must be heterozygotes (DR). 
It would seem, therefore, that the homozygous dominant is externally 
distinguishable from the heterozygous one. 
We see further in the table that the abnormality is sometimes not trans- 
mitted (cows No. 35, No. 70 and No. 71). I have endeavoured to get some 
further details as to the numerical ratio between the abnormals and normals. 
The only data obtainable were the results from crossings between abnormal 
sires and normal dams at the Kanei Farm in Teshio province and at the Ne- 
muro Farm in the province of Nemuro. Each farm now owns two bulls of 
the second type, all being descendants from "Express." In the past two years 
