528 MURIDAE—APODEMUS 
Until the young were three weeks old, the mother frequently 
carried them back to the nesting-box, usually lifting them by 
the side of the belly, midway between the fore and hind legs, 
the mother’s erect head raising them completely above the 
ground. The dam soon discovered that her load must be 
changed at the narrow entrance to the nesting-box, and so 
dropping the young ones outside, she entered, and turning 
round dragged each baby in head foremost. Occasionally the 
parents attempted to drag older children into the nest. 
Mr Barrington’s remarks are confirmed by Dr Henry 
Laver,’ who observed copulation, and found that the periods 
of gestation and cestrus seem to be respectively twenty-four to 
twenty-five and six days, copulation taking place a few hours after 
the birth ofa litter, and six days after a previous ineffective pairing. 
It must be noted that Mr Barrington’s observations are 
in one or two respects abnormal. The original mice having 
been taken in the autumn, did not produce young until the 
following spring, when five and a half months old. Had they 
been the young of early spring litters, they might have been 
expected to breed when younger. 
A female in the possession of Monsieur Fernand Lataste, 
being deprived of her young, imposed upon herself the task 
of rearing a strange baby, and Mr F. H. Parrott informed 
Mr Cocks that one he had reared a litter of Grass Mice. 
As a result of his examination of thirty-four litters, Mr 
Adams thinks that the average number of young per litter 
is about five; he has seen one litter of nine young, three 
of seven, five of six, thirteen of five, nine of four, two of 
three, and one of two. Mr Adams has found young in every 
month of the year excepting January, and, very curiously, June 
and July. 
The breeding habits probably resemble those of the House 
Mouse”; the young cling to the mother’s teats just like other 
mice,’ and it is extraordinary to what a pace she attains with 
1 Field, 19th August 1905, 378 ; and zz /7¢. 2 Lataste. 
3 Gilbert White, Letter lii. to Daines Barrington, 26th March 1773; R. M. 
Barrington, of. cit.; J. J. Briggs, Zoologist, 1856, 5311 (? species doubtful) ; Victor 
Fatio witnessed a female ploughed out of the ground with the young attached to her 
hairand tail (p. 213). The famous incident which made Burns write of a “wee 
sleekit, cowrin’, tim’rous beastie” may be recalled. See also Rope, Zoologist, 1873, 
