ps;" and the animal was doubtless
insectivorous. By Professor Owen, the highest living authority on
the subject, _Amphitherium_ is believed to be a small Marsupial,
most nearly allied to the living Banded Ant-eater (_Myrmecobius_)
of Australia (fig. 158). _Amphilestes_ and _Phascolotherium_
(fig. 184) are also believed by the same distinguished anatomist
and palaeontologist to have been insect-eating Marsupials, and
the latter is supposed to find its nearest living ally in the
Opossums (_Didelphys_) of America. Lastly, the _Stereognathus_ of
the Stonesfield Slate is in a dubious position. It may have been
a Marsupial; but, upon the whole, Professor Owen is inclined to
believe that it must have been a hoofed and herbivorous Quadruped
belonging to the series of the higher Mammals (_Placentalia_).
In the Middle Purbeck beds, near to the close of the Oolitic
period, we have also evidence of the existence of a number of
small Mammals, all of which are probably Marsupials. Fourteen
species are known, all of small size, the largest being no bigger
than a Polecat or Hedgehog. The genera to which these little
quadrupeds have been referred are _Plagiaulax, Spalacotherium,
Triconodon_, and _Galestes_. The first of these (fig. 184, 4)
is believed by Professor Owen to have been carnivorous in its
habits; but other authorities maintain that it was most nearly
allied to the living Kangaroo-rats (_Hypsiprymnus_) of Australia,
and that it was essentially herbivorous. The remaining three
genera appear to have been certainly insectivorous, and find
their nearest living representatives in the Australian Phalangers
and the American Opossums.

Finally, it is interesting to notice in how many respects the
Jurassic fauna of Western Europe approached to that now inhabiting
Australia. At the present day, Australia is almost wholly tenanted
by Marsupials; upon its land-surface flourish _Araucarioe_ and
Cycadaceous plants, and in its seas swims the Port-Jackson Shark
(_Cestracion Philippi_); whilst the Molluscan genus _Trigonia_
is nowadays exclusively confined to the Australian coasts. In
England, at the time of the deposition of the Jurassic rocks,
we must have had a fauna and flora very closely resembling what
we now see in Australia. The small Marsupials, _Amphitherium,
Phascolotherium_, and others, prove that the Mammals were the same
in order; cones of Araucarian pines, with tree-ferns and fronds
of Cycads, occur throughout the Oolitic se