the one here represented, although the wood-cut is made from a better
specimen than is often found. We have, however, remains enough
to establish unquestionably the fact of their existence in the
Carboniferous period, and to show us that the type of Articulates was
already represented by all its classes.

[Illustration]

Not so with the Vertebrates. Fishes abound, but their class still
consists, as before, of the Ganoids, those fishes of the earlier
periods built on the Gar-Pike and Sturgeon pattern, and the Selachians,
represented now by Sharks and Skates. In the Carboniferous period we
begin to find perfectly preserved specimens of the Ganoids, and the
adjoining wood-cut represents such a one. Of the old type of Selachians
we have again one lingering representative in our own times to give us
the clue to its ancestors,--as the Gar-Pike explains the old Ganoids,
and the Chambered Nautilus helps us to understand the Chambered Shells
of past times. The so-called Port-Jackson Shark has features which were
very characteristic of the Carboniferous Sharks and are lost in the
modern ones, so that it affords us a sort of link, as it were, and a
measure of comparison, between those now living and the more ancient
forms. It is an interesting fact that this only living representative of
the Carboniferous Shark should be found in New Holland, because it is
there, in that isolated continent, left apart, as it would seem, for a
special purpose, that we find reproduced for us most fully the character
of the Animal Kingdom in earlier creations.

[Illustration]

The first Mammalia in the world were pouched animals, having that
extraordinary attachment to the mother after birth which characterizes
the Kangaroo. In New Holland almost all the Mammalia are pouched, and
have also the imperfect organization of the brain, as compared with the
other Mammalia, which accompanies that peculiar structural feature; and
although the American Opossum makes an exception to the rule, it is
nevertheless true that this type of the Animal Kingdom is now confined
almost exclusively to New Holland. Whether this living picture of old
creations in modern garb was meant to be educational for man or not, it
is at least well that we should take advantage of it in learning all it
has to teach us of the relations between the organic world of past and
present times.

There were a great variety of the Selachians in the Carboniferous
period. The wood-cuts below