140 Mr Hecipe, Notes on the Proportion of the Sexes in Dogs. 
The great excess of dogs produced by Greyhounds in the winter 
months is not seen in Collies, on the contrary it is during those 
months that the lowest proportion of dogs is recorded. My own 
interpretation of the cause of this difference is, that while amongst 
Greyhounds most of the few litters born at this period were 
probably conceived, in consequence of some carelessness of the 
kennel-man, by bitches in training and not carefully nurtured for 
breeding, amongst Collies the conception of pups born during 
these months takes place in bitches which are not so affected but 
which, on the contrary, are probably in specially good condition 
(i.e. July to October). In a future communication I propose to 
submit evidence in favour of this view. 
A comparison of the columns showing the extreme variation 
of dogs per 100 bitches born and of the difference in these 
proportions, for Collies (Table V) and for Greyhounds (Table II) 
shows, that while among Collies the greatest difference occurs as 
a rule in those months iu which the largest number of pups are 
born, in Greyhounds the greatest difference is associated with the 
fewest births. This may be interpreted as indicative that the 
latter are more susceptible to annual variation of climate, 
temperature, &c., than the former, an interpretation which is 
perhaps strengthened when the structure and habits of the two 
breeds and the life they lead are compared. 
Evidence in favour of this interpretation I must also defer to 
a future communication. 
Breeders’ Schedule Returns. 
In these returns the breeders applied to supplied me with 
details of the sex of every pup produced in each litter whenever 
that was possible. In a few cases still-born pups were produced 
in a condition which did not admit of sex determination ; in these 
cases, and in all others regarding which there was any doubt, the 
litters are not included in the figures given below. 
The totals for each breed are given in Table VII. 
As in Table IV, I have again divided the breeds into Large 
dogs and Terriers. The pups per litter for the Large dogs, as 
returned in the Schedules, are - 57 smaller than those given in the 
Kennel Register (Table IV), for the Terriers they are practically 
the same. Here again it is shown that the bigger dogs have the 
larger litters and, with the exception of Pointers, this is as true 
in detail as was seen in the Kennel Register records. There is 
undoubted correlation between the size of the animal and its 
fertility per litter. 
The pups per litter for Collies and Mastiffs are closely 
approximate in both Tables, while the Schedule returns for 
