liv 
INTRODUCTION. 
and the usual result is that two closely allied races, classed as representative species, become fanned. 
Such pairs of allied species on the two sides of a continent, or in two detached areas, are very nume- 
rous ; and their existence is only explicable on the supposition that they are descendants of a parent 
form which once occupied an area comprising that of both of them, — that this area then became 
discontinuous, — and, lastly, that, as a consequence of the discontinuity, the two sections of the parent 
species became segregated into distinct races or even species.” 
In his ‘Geographical Distribution of Animals’ Mr. Wallace treats New Zealand and her 
satellites as forming a subregion of Australia. The Australian, or “ great insular region of the 
earth,” is divided by him into four subregions, distinguished as the Austro -Malayan, Australian, 
Polynesian, and New Zealand. The last-named subregion is made to include Norfolk Island, Phillip 
and the Nepean Isles, Lord Howe’s Island and the Kermadec Isles on the north, the Chatham Islands 
on the east, the Auckland, Macquarie, Emerald, Campbell, Antipodes, and Bounty Islands on the 
south and south-east. 
Other prominent writers on the subject have claimed for New Zealand full recognition as a 
separate biological province, quite distinct from Australia and every other region of the earth. My 
own study of the subject having brought me to the same conclusion, I propose to examine here, very 
briefly, the grounds upon which Mr. Wallace links New Zealand to Australia as contiguous sections 
of one biological region. He admits, of course, that there is a “wonderful amount of speciality, 
but he contends that “ the affinities of the fauna, whenever they can be traced, are with Australia or 
Polynesia.” 
If we take Mr. Wallace’s own table of the geographical distribution we find, on a careful 
analysis, that out of twenty-eight families stated to be common to Australia and New Zealand, thiee are 
included in error, namely Sittidse, Dicseidge, and Pandionidae, thus reducing the number to twenty-five. 
Of these, fifteen are admitted by him to be cosmopolitan, and may therefore be discharged from the 
present inquiry. Of the remaining ten, four belong to the Old World, four to the Oriental, Ethiopian, 
Austro-Malayan, and Polynesian regions respectively, and one highly specialized family, the Spheniscidae, 
to the south temperate regions, leaving thus only one family, the Paridse, as restricted in its range 
to the two countries. This family is represented in New Zealand by a single genus, Gerthiparus, 
about the true position of which there is considerable doubt, and this genus again is represented by 
a single species, so that, as regards the mere distribution of families, the argument altogether 
fails. Let us now examine the far more important question of identical or representative 
genera and species in the two countries, for this after all is the true test of a common origin. 
Of the twelve, genera of Australian birds which he treats as belonging equally to New Zealand, 
it may be remarked that two (namely Graucalus and Acanthochcera ), each of them represented 
by a single species, have only occurred in New Zealand as accidental straggieis, at veiy long 
intervals; that Tribonyx, as already explained at p. xiv, has never actually oceuired in a wild state; 
and that Orthonyx and Hieracidea have, on further investigation of their characters, been replaced by 
two endemic genera, Clitonyx and Harpa. Of the remaining seven, two alone (Gerygone and Sphencea- 
cus ) are characteristic of Australia, the others ranging over a great part of the southern hemisphere ; 
thus, Platycercus is spread over New Guinea and Polynesia, as well as Australia, Phipidura extends to 
India, and Zoster ops through Polynesia and the Malay Archipelago to India and Africa. Of the 
five species mentioned by Mr. Wallace as being identical in Australia and New Zealand, it may be 
mentioned that three (Acanthochcera cccrunculata, Graucalus melanops, and llirundo nigricans) are 
among our rarest stragglers from abroad, and that the Shining Cuckoo ( Chrysococcyx lucidus ) is an 
