244 
POUCHED MAMMALS. 
instance on record of one swimming across an arm of the sea two miles in width,— 
half of the distance being against a strong wind and current. 
The writer just quoted states that the principal food of kangaroos “ appears to 
be the tender sprouts of small shrubs and heather, quite as much as grass; but 
there is a small kind of spike-grass, brown on the under-side, called the kangaroo- 
grass, to which they are very partial. They will also come at night into the small 
bush-enclosures, and nibble off the young blades of wheat, oats, etc.” When 
feeding off the ground, they do not always use the fore-paws as a support, but 
often merely crouch down. Occasionally they may be seen in the upright position, 
browsing from trees. As regards breeding-habits, it appears that in the great grey 
kangaroo the pairing-season is either in January or February, although there is 
some irregularity in this respect. Only a single young is produced at a birth, after 
an exceedingly short period of gestation; and when first transferred to the pouch 
of its mother, the length of the offspring is scarcely more than an inch. When the 
young kangaroo is sufficiently developed to move freely by itself, it becomes 
detached from the teat to which it at first adhered; but it remains chiefly in the 
pouch till able to run by the side of its parent. “ Even then, when danger is near, 
it tumbles head-over-heels into the pouch for protection; and it is wonderful how 
quickly the old doe can pick up the ‘joey’ when running at full speed, and shove 
it into the pouch, its pretty little face always outside. There she carries it till 
hard pressed, when the love of life overcomes the love of the mother, and she then 
casts it away to save herself.” The “joeys” become strong runners; and by 
Christmas, leave their parents and learn to shift for themselves. 
The half-dozen medium-sized species collectively known as rock- 
wallabies, one of which is represented in the accompanying illustra¬ 
tion have the extremity of the muzzle completely naked, and differ from the true 
wallabies by the shortness of the claw of the fourth hind-toe, and also by the long 
cylindrical tail being thinner and more or less distinctly tufted at its extremity. 
None of them have any trace of a tusk in the upper jaw. The yellow-footed 
rock-wallaby ( Petrogale xanthopiis) —that given in our figure—is the largest 
species, and is distinguished from the rest by its brilliant coloration, more 
especially the alternate brown and pale yellow rings on the tail. The general 
colour of the long and silky fur is grey on the back, with a well-defined black 
streak running from between the long ears to the middle of the trunk. The 
cheeks are marked by an oblique white stripe below the eye, and by a yellow spot 
above the same. The ears are yellow externally, with their inner sides edged 
with white, except at the tips; and the sides of the body are marked by a pure 
white stripe from the elbow to the hip. The chin and under-parts are also pure 
white; and there is likewise a patch of the same colour on the outer side of the 
knee; while the lower portions of the limbs, including the feet, are yellow. On 
the tail the rings occupy only the upper surface, the inferior aspect being uniformly 
yellowish. This species is restricted to South Australia. The common brush¬ 
tailed rock-wallaby (P. penicillata), from the coast districts of the eastern side of 
the continent, is more soberly coloured; the general tint of the coarse hair being 
dull brown, tending to rufous on the hind-quarters. In the male, the length of 
the head and body reaches 28J inches; and that of the tail, exclusive of the hair 
Rock-Wallabies. 
