THE WATER RAT 497 
renders the microtines generally such easy victims of pit- 
traps. 
The British Water Rat has not been frequently tamed, but 
M. Lataste kept specimens of two continental forms,’ some of 
the peculiarities of which have been mentioned above. Mr 
English* has also caged them; though thriving well in 
captivity, they are rather troublesome, requiring a large tank of 
water,® which they immediately soil with their droppings and 
making their cage and nest constantly wet after their aquatic 
excursions. Cocks has also frequently caged numbers of them, 
but for the above reason he has never kept them systematically, 
but has always used them as required, as very suitable food for 
Wild Cats. Some of M. Lataste’s captives showed a tendency 
to arrange their bed near the water in such a position that they 
could drop into that element unseen if disturbed; although 
very assiduous in working at their nest they evidently felt most 
secure in the water. 
The intelligence of the Water Rat is considerable, and it is 
capable of recognising particular persons; but in the opinion 
of M. Lataste it is in this respect inferior to the Brown Rat. 
The maximum age attained in the London Zoological 
Gardens is 16 months,’ but the natural life of the animal is 
probably much longer. 
Sub-family Murine. 
Characters:—The members of this sub-family, the typical 
mice and rats, are of varied external appearance and_ habits. 
They differ from the M/zcrotzne chiefly in being more perfectly 
adapted for gnawing; in retaining a preference for, and 
consequently a dentition suitable to the treatment, of, a soft 
and succulent diet; and in leading more active and_ less 
earthbound lives. Their eyes and external ears are always 
well developed. 
1 A. sapidus and A. scherman 2 In Millais, ii., 293, etc. 
% Tf not allowed to swim their eyes become closed by secretion of an oily matter 
drying like white wax (English). 4 P. Chalmers Mitchell. 
