e tropical parts of the Australian region.

The reptiles, so far as they go, are quite in accordance with the birds.
The lizards belong to two genera, Lygosoma, which has a wide range in all
the tropics as well as in Australia; and Naultinus, a genus peculiar to New
Zealand, but belonging to a family--Geckonidae--spread over the whole of
the warmer parts of the world. Australia, with New Guinea, on the other
hand, has a peculiar family, and no less than twenty-one peculiar genera of
lizards, many of which are confined to its temperate regions, but no one of
them extends to temperate New Zealand.[126] The extraordinary lizard-like
_Hatteria punctata_ of New Zealand forms of itself a distinct order of
reptiles, in some respects intermediate between lizards and crocodiles, and
having therefore no affinity with any living animal.

The only representative of the Amphibia in New Zealand is a solitary frog
of a peculiar genus (_Liopelma hochstetteri_); but it has no affinity for
any of the Australian frogs, which are numerous, and belong to eleven
different families; while the Liopelma belongs {484} to a very distinct
family (Discoglossidae), confined to the Palaearctic region.

Of the fresh-water fishes we need only say here, that none belong to
peculiar Australian types, but are related to those of temperate South
America or of Asia.

The Invertebrate classes are comparatively little known, and their modes of
dispersal are so varied and exceptional that the facts presented by their
distribution can add little weight to those already adduced. We will,
therefore, now proceed to the conclusions which can fairly be drawn from
the general facts of New Zealand natural history already known to us.

_Deductions from the Peculiarities of the New Zealand Fauna._--The total
absence (or extreme scarcity) of mammals in New Zealand obliges us to place
its union with North Australia and New Guinea at a very remote epoch. We
must either go back to a time when Australia itself had not yet received
the ancestral forms of its present marsupials and monotremes, or we must
suppose that the portion of Australia with which New Zealand was connected
was then itself isolated from the mainland, and was thus without a
mammalian population. We shall see in our next chapter that there are
certain facts in the distribution of plants, no less than in the geological
structure of the country, which favour the latter view. But we must on any
supposition p