PRESIDENTIAL ADDRESS. 137 
amined mice from the Darling Downs district in Queens- 
land, and found these to be the same species. 
As regards variation in size, Mr. J. B. Clarke, of Vic- 
toria, after seeing some hundreds of thousands, says they 
were almost as equal as peas in a pod. He saw little varia- 
tion in colour—an occasional piebald one, and only one or 
two albinos in the season. In reference to one of the mice 
from Tocumwal, with light colouring on its under surface, 
Mr. Longman says that this is interesting in view of the 
fact that Collett’s specimen from Coomooboolaroo, N. 
Queensland, collected in 1884, and identified by Thomas as 
Mus musculus, had the under side nearly white.’ 
Summary of the Information Available—Before giving 
in detail the information collected, it may be useful to sum- 
marise this, and indicate the salient points of scientific in- 
terest. It appears that the common house mouse, which in 
the mild climate of Australia has taken much to the fields, 
as well as to houses, outhouses and barns, multiplied pro- 
digiously during the season under review. This was due 
to the abundance of suitable food, first of all from stacks of 
wheat left over from the previous year, then from grain 
shed in the fields as the result of unusual wind and rain 
storms, and finally from the vast accumulations of fresh 
grain stored in the neighbourhood of these previous food 
supplies. These conditions were more or less prevalent over 
the wheat areas of New South Wales, Victoria and South 
Australia, leading to a general and almost contempora- 
neous increase over vast areas. Given an abundant food 
supply, no natural enemies existed in Australia in suffi- 
cient numbers to cope with such prolific breeders. The 
mice, having exhausted the food in the fields, or being dis- 
turbed by ploughing, then sought new stores, and invaded 
the stacks, gnawing the bags. The wheat escaped, and the 
*R. Collett; Zool. Jahr., 1887, p. 839. 
