Mr Heape, Notes on the Proportion of the Sexes in Dogs. 133 
roughly, November to May is the time of year when conception 
usually takes place. 
From March to June, when births are most frequent, the 
proportion of dogs per 100 bitches is remarkably constant, varying 
from 113'57 to 119T6, a difference of 5 '59, the average being 
116'29; whereas from July to February, when births are less 
frequent, there is a much wider variation, namely from 110'.99 
(September) to 195'45 (December), a difference of 84'46, the 
average being 122'1 dogs per 100 bitches. 
In only three of these months, viz. August (11 9 0), September 
(110'99), and February (113 96) is the proportion of dogs lower 
than that recorded for any of the months, March to June ; in all 
other months the proportion of dogs is higher, especially in the 
four winter months from October to January, when the proportion 
ranges from 144'61 to 195 45, the average being 13227 dogs per 
100 bitches. 
The column in Table II showing the extremes of variation for 
the years 1887—1890 indicates a very similar result. The lowest 
proportion of dogs recorded for the four months March to June 
varies from 107 to 112, a difference of 5, while the highest 
proportion varies from 117 to 127, a difference of 10. From July 
to February, however, the lowest figures range from 93 to 171, 
the highest figures from 127 to 500. 
In the same way the differences range from 9 to 16 from 
March to June, and from 11 to 329 from July to February, while 
the greatest differences occur during the winter months, October 
to December, when the highest proportion of dogs is born. 
The mean of the variation during the years 1887 — 1890 shows 
this result more markedly. In this column it is seen that in all 
months from February to July less than 120 dogs per 100 bitches 
are registered, while in all from August to January, with the 
single exception of September, the proportion of dogs is more 
than 120. 
An examination in detail of my figures shows that throughout 
each year, month by month, there is almost invariably a marked 
preponderance of dogs recorded. The only months in which 
bitches predominate occur irregularly as follows: July, 1888, 95 
dogs; February, 1889, 95; August, 1889, 93; September, 1890, 
96 per 100 bitches; while in a series of years there is no month 
which shows a preponderance of bitches. 
Again, while the annual total invariably shows a higher pro- 
portion of dogs than bitches there is no year in which this is 
markedly the case, the extreme variation of the totals for 1887 — 
1890 being 6. 
The year in which only 115 dogs were recorded was in 1889, 
when the proportion of dogs fell especially low in both February 
and August of that year. 
