roo mice run the true rats and
mice a close race in every particular. And it is worth notice, in this
connection, that the one marsupial family which could compete with
higher American life, the opossums, are really, so to speak, the monkey
development of the marsupial race. They have opposable thumbs, which
make their feet almost into hands; they have prehensile tails, by which
they hang from branches in true monkey fashion; they lead an arboreal
omnivorous existence; they feed off fruits, birds' eggs, insects, and
roots; and altogether they are just active, cunning, intelligent,
tree-haunting marsupial spider-monkeys.

Australia has also one still more ancient denizen than any of these, a
living fossil of the very oldest sort, a creature of wholly immemorial
and primitive antiquity. The story of its discovery teems with the
strangest romance of natural history. To those who could appreciate the
facts of the case it was just as curious and just as interesting as
though we were now to discover somewhere in an unknown island or an
African oasis some surviving mammoth, some belated megatherium, or some
gigantic and misshapen liassic saurian. Imagine the extinct animals of
the Crystal Palace grounds suddenly appearing to our dazzled eyes in a
tropical ramble, and you can faintly conceive the delight and
astonishment of naturalists at large when the barramunda first 'swam
into their ken' in the rivers of Queensland. To be sure, in size and
shape this 'extinct fish,' still living and grunting quietly in our
midst, is comparatively insignificant beside the 'dragons of the prime'
immortalised in a famous stanza by Tennyson: but, to the true
enthusiast, size is nothing; and the barramunda is just as much a marvel
and a monster as the Atlantosaurus himself would have been if he had
suddenly walked upon the stage of time, dragging fifty feet of
lizard-like tail in a train behind him. And this is the plain story of
that marvellous discovery of a 'missing link' in our own pedigree.

In the oldest secondary rocks of Britain and elsewhere there occur in
abundance the teeth of a genus of ganoid fishes known as the Ceratodi.
(I apologise for ganoid, though it is not a swear-word). These teeth
reappear from time to time in several subsequent formations, but at last
slowly die out altogether; and of course all naturalists naturally
concluded that the creature to which they belonged had died out also,
and was long since numbered with the