Bullee. — Illustrations of Darwinism. 97 



and, pending an opportunity of forwarding it to me, it was 

 kept tethered by a flax-string in the rnarae or open court- 

 yard. A passing Maori unconsciously snapped the string 

 with his foot, and, unfortunately for me and for science, this 

 "rara avis in tcrris " made its escape. More than forty years 

 have elapsed since this occurrence, and I have never so much 

 as heard of the capture of another Pukunui ! 



In this connection, and also as marking the tendency 

 towards extinction in certain lines, it is of interest to notice 

 that the Ralline genus Notornis was contemporary with the 

 smaller species of Moa, and that the bones of the living bird 

 obtained in Otago differ so much from those of the fossil 

 remains discovered by Mr. Walter Mantell at Waingongoro, 

 in the North Island, and referred by Professor Owen to a 

 form which he named Notornis viantelli, in honour of the 

 discoverer, that Dr. A. B. Meyer, of Dresden, proposes to 

 discriminate two species, distinguishing the southern form as 

 Notornis hochstetteri, in compliment to the Austrian explorer. 

 Assuming Dr. Meyer to be right in his determination, we 

 have here a beautiful instance of representation, the North 

 Island species having long since disappeared, whilst the South 

 Island species is verging on extinction. 



I think I have now noticed all the main points bearing on 

 this question arising out of a study of the birds of the North 

 and South Islands. But it is to the smaller insular areas 

 that we naturally look for the strongest proofs in support of 

 our theory, because the conditions there are altogether more 

 favourable. Let us first take the Chatham Islands, lying 

 about four hundred miles to the south-east of Wellington. 

 It is very clear that there has been no land communication 

 between the Chathams and New Zealand since the con- 

 tinental submergence. This has allowed time for the pro- 

 duction by natural selection and the survival of the fittest 

 of several distinct species. Now, let us see what we have. 

 Notably, a new species of Bell-bird (Anthornis mclanocepliala) 

 has come into existence — a much larger and finer species 

 than our Korimako (Anthornis melanura), although presenting 

 the same adolescent and sexual phases of plumage. But the 

 curious thing about it is that, side by side with this endemic 

 species, our Bell-bird is also to be found in the Chatham 

 Islands and on the adjacent islets (Pitt Island and Mangare). 

 To my mind the only explanation of this is the same that I 

 have given in a former paper (Trans. N.Z. Inst., vol. xxiv., 

 p. 65) for the occurrence side by side of Platycercus unicolor 

 and Platycercus erythrotis on Antipodes Island — namely, that 

 the smaller species owes its existence there to a compara- 

 tively-recent colonization, the result of some accidental flight 

 or migration from the mainland, — with this difference : that in 

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