660 MURIDA—MUS 
Mice at the sixth day commenced to be clothed, at the 
thirteenth day they were completely clothed, and had the 
external auditory meatus open ; at the fourteenth to the fifteenth 
day the eyes opened; on the nineteenth day (but sometimes 
as early as the sixteenth) they were able to leave the mother, 
although they would suckle for a few days more if opportunity 
permitted ; at this age their parents do not molest them, but 
soon after they will massacre the young. The male will 
copulate when 14 months old, and a female 116 days old 
bore young after copulation with a male of her own age. 
Lataste observed them to be very voiceful, crying at birth. 
Saint-Loup’ finds the rate of growth to be most rapid 
immediately after birth; it then decreases continually during 
eighteen days ; from the nineteenth to the twenty-second day 
it rises again, but without attaining a quarter of the initial 
rate; afterwards it fluctuates. 
Despite their disagreeable odour, which impregnates their 
cages and everything they touch, many find tame House Mice 
attractive pets; there is a National Mouse Club, and “shows” 
are held at which prizes are awarded to the best representatives 
of the very numerous recognised classes or breeds. These 
mice have long been tamed, and certain of the coloured races 
are of respectable antiquity; thus Merrett (Pzax, 167, 1667) 
was acquainted with white, ashy and dark varieties, and it is 
worth noting that he does not speak of coloured rats. Brehm 
( Thierleben, ii., 134) states that tame mice are fond of spirits, 
but Lataste found that pure rum had no attraction for those 
kept by him. The latter writer describes his captives as 
being essentially, though not absolutely, nocturnal; with well- 
developed senses, and intelligent, though not so well endowed 
in these respects as the Brown Rat ; they are excellent climbers, 
with feebly, but really, prehensile tails, which are especially 
useful to them in balancing exercises, in which they excel; 
they have a sense of property, and are peculiarly gentle, 
perhaps from long domestication, and readily handled; they 
are friendly to each other, unless treated foolishly or badly 
fed; a single cage, however, will only hold the parents and 
young, and the young must be removed when they become 
1 R, Saint-Loup, Bull. Zool. de France, 1893, 242. 

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