148 Mr Heape, Notes on the Proportion of the Sexes in Dogs. 
wide generalisations, but there is evidence enough to show, as for 
instance in the case of Mastiffs, that the sire does also exert 
influence, and therefore that, if fertilisation of the ovum is effected 
by sperm of the complementary sex, a large proportion of the 
sperm produced by this animal must have been of one sex. 
Finally, I have abstracted figures to test the opinion, held by 
many breeders of stock, that while in some years males are pro- 
duced in marked excess, in others females predominate. 
The figures at my disposal are far too few to admit of 
elaborate analysis but, taking Basset hounds and Dachshunds as 
representative of the two classes of dogs, I find that, during the 
16 years Mr Millais bred Basset hounds, dog pups were produced 
in excess 11 years and bitches 1 year, while in 4 years the sexes 
were equal; and during the 11 years Mr Mudie bred Dachshunds, 
dog pups were in excess 6 years, bitch pups 4 years and the sexes 
equal 1 year. The racial tendency to produce a greater or less 
proportion of one sex, to which I have referred above, no doubt 
influences this comparison ; Basset hounds produce a very much 
larger proportion of dog pups, on an average, than is the case 
with Dachshunds (Table VII), so it is not surprising to find a 
more even balance, per year, among the latter. 
It is of special interest to note that, taking 9 years for which 
I have results from both kennels, only two of them show widely 
divergent results, and that in three consecutive years the results 
are: for (1), both kennels produced a small excess of bitch pups ; 
for (2), a specially large proportion of dog pups were born in both, 
Mr Millais’ results showing 180, Mr Mudie’s 380 above the 
average ; while for (3) there is a similar result, Mr Millais 
breeding 123’4 and Mr Mudie 162'5 above the average. 
It is quite possible this is purely a chance coincidence and I 
don’t attribute any great importance to it. The methods of feeding 
and housing dogs in large breeding kennels must eliminate much 
of the effect of variation in the seasons which might be supposed 
to exert influence. 
Trustworthy records of the breeding of farm stock would 
supply what is needed to test this view and it is unfortunate that 
they are so difficult to obtain regularly and on a sufficiently large 
scale. For pheasants it is, I think, undoubtedly true that there is 
a marked difference in the proportion of cocks and hens driven 
to the guns in different years, and 1 am strongly disposed to 
believe there is truth in the popular belief. 
Conclusions. 
We have dealt with 19916 dog pups, 16951 bitch pups, a 
total of 36867 pups, of which the proportion of dogs per 100 
