84 Transactions. — Zoology. 



way down the west coast to Wanganui. But all the specimens 

 I have seen from the east coast are almost black in plumage, 

 even the feet being blackish instead of whitish-brown as in the 

 ordinary bird. So far no attempt has been made to raise this 

 form to the rank of a species, or even of a sub-species ; but the 

 fact remains that the birds from this part of the country are 

 always dark-coloured, and, as such, readily distinguishable 

 from the common Kiwi. And, as I have mentioned in my 

 " Birds of New Zealand " (vol. ii., p. 310), there is likewise a 

 rufous-coloured form, with plumage of a very peculiar texture 

 (" Kiwi-kura" of the Maoris), which I found breeding true in 

 the Pirongia Banges ; but, as this bird inhabits the same dis- 

 trict as Apteryx mantelli, it can only be regarded as a variety. 

 Nevertheless it shows very clearly the latent tendency to- 

 vary. 



Apteryx lawryi is the largest of these species, as Apteryx 

 haasti (which is next in size) is the most handsome, owing 

 to its chestnut-and-brown dappled plumage. Apteryx lawryi 

 runs as it were in parallel lines with Apteryx mantelli and 

 Apteryx australis, as Apteryx haasti does with Apteryx oiveni 

 and Apteryx occidentalis. But, whether all these species be 

 accepted as distinct, or some of them be regarded as mere 

 varieties of others (which will always be debatable ground),, 

 there can be no doubt whatever that they have all come from 

 a common parent stock, and that within a period of time, 

 geologically speaking, comparatively recent. Going back to 

 earlier times, and reasoning by analogy, w 7 e may venture to- 

 infer that the remote ancestor of the degenerate parent form 

 was a volant bird — probably one tolerably well furnished with 

 wings and tail, with a proportionately large head and short 

 bill, with the muscles of the posterior limbs far less developed 

 than in the Kiwi, and with very different plumage, both as 

 to form and texture. 



It may be asked how 7 it is that we find the Kiwi developing 

 a long stiletto-like bill, whilst another race of wingless birds, 

 the Moas, belonging to the same order and inhabiting the 

 same country, were perfecting themselves in an entirely oppo- . 

 site direction. But it must be remembered that, according to 

 the ascertained laws of variation, divergence of character in 

 opposite directions may take place even among members of 

 one and the same species, at one and the same time, and 

 within the same geographical area. Isolation, for such & 

 purpose, does not necessarily mean insulation, as some writers 

 appear to assume. Wallace puts it very clearly : " Isolation 

 will often be produced in a continuous area whenever a species 

 becomes modified in accordance with varied conditions or di- 

 verging habits. For example, a wide-ranging species may, in 

 the northern or colder part of its area, become modified in one. 



