Mr Heape, Notes on the Proportion of the Sexes in Dogs. 135 
Table III. 
Stock Keeper, Kennel Register, 1889 — 1891. 
Breeds 
Dogs 
Bitches 
Total 
Dogs 
per 100 
bitches 
Litters 
Pups 
per 
litter 
Collies 
St Bernards.. 
Spaniels 
5040 
4290 
9330 
117-48 
1247 
7-48 
Bull Terriers 
Irish Terriers 
Fox Terriers. 
2216 
1986 
4202 
111-58 
752 
5-59 
The difference is 5"9 and, from these figures, it seems per- 
missible to conclude that the largest number of dog pups is 
obtained amongst the largest litters. 
It is true that individual entries such as, for instance, English 
White Terriers, Black and Tan Toy Terriers, &c., and Bulldogs, 
do not conform to this conclusion, but in each of these isolated 
cases we are dealing with very small numbers and for that reason 
a detailed comparison is not justified. As a class distinction the 
comparison I have made is, I think, justifiable and I may add 
that the figures given below, derived from the Schedules sent to 
breeders, in which an accurate record of each litter is given, bear 
out this conclusion, though the difference is less, being 2 - 63. 
Taking each breed individually there is some evidence that the 
production of a high percentage of males is associated with in- 
breeding. Many breeders hold a strong opinion that this is the 
case ; I have not sufficient evidence here to show the fact, but 
there are some indications of its probability. 
Concerning fertility, it is remarkable that the average number 
of pups per litter is so closely in accord with the actual size of the 
breed of dog concerned (Table IV). From Bloodhounds to Toy 
Terriers there is an almost regular correlation between size and 
fertility per litter. 
In the absence of assurance that all pups born are registered, 
one is naturally disposed to imagine it is possible that a larger 
proportion of pups are destroyed among small breeds than among 
large breeds of dogs, that the relation shown here is an artificial 
one due to the necessity of reducing the strain of motherhood 
