184 MAMMALS

-atrival of the pack. With his fore-paws he seizes by
the head the first dog that approaches him, and as he
is more firmly balanced than his assailant, he holds
the dog’s nose beneath the water as long as he can.
Unless a second dog comes speedily to the rescue the
first is inevitably drowned. If a companion arrives
to rescue him, he is so confused by this unexpected
bath that he regains the bank as quickly as possible,
and has no further desire to attack. A strong and
courageous old male can thus hold his own against
twenty or thirty dogs, drowning some and frightening
others, and the hunter is obliged to intervene and put
an end to this energetic defence by a bullet.’ Kan-
garoos have even been known to kill men by drown-
ing them.

There are about two dozen species of kangaroos ;
the big ones, like Macropus giganteus and M. rufus,
are over eight feet in length, counting in the tail, and
can jumpa fence eleven feet high and leap fifteen feet
on the flat. The tail is not used to spring with from
the ground. No kangaroo, unless by accident on
uneven ground, touches anything with his tail when
going fast. His taii merely acts as a balance when
he is on the move, and is carried horizontally.

MONOTREMATA.—This is the last order of
mammals; and they are mammals without mamma,
the mother’s milk exuding from groups of pores in
the skin. In many respects they resemble reptiles, in
some they resemble birds, but really they have points
of resemblance with every creature present and past,
and seem to be built up of missing links and