THE LIFE OF MAMMALS 
harmful, originating and apt in the remote history of this ‘‘last 
leaf”? on the ancestral tree of American zodlogy,—a good 
habit gone wrong! 
In addition to the common opossum no less than 22 spe- 
cies are catalogued in Central and South America. Many of 
them are no larger than mice,—for example, the murine opos- 
sum, which strays across our southwestern border; others are 
little known, but all seem much alike in their manner of life. 
The notable exception is the yapock, a water-loving species 
about the size of a large rat, with webbed hind feet, and aquatic 
preferences. It inhabits the rivers from Guatemala to southern 
Brazil, is comparatively rare, and is believed to live chiefly on 
crustacea, insects, and an occasional fish. ‘‘The female has a 
well-developed pouch, in which the young, usually five in num- 
ber, are carried for some time; and it will be obvious that dur- 
ing that period the creature must refrain from entering the 
water. Later on the young accompany their parent to the river, 
and are exercised by her in swimming and in diving.” 
This ends the list of eutherian mammals. 
4, 
(J 
RABBIT BANDICOOT. 
520 
