96 Transactions. — Zoology. 



from the normal type of a plover's bill is congenital, being 

 present in the unhatched embryo. Then, again, what is the 

 Bock Wren (Xenicus gilviventris) but an extreme development 

 of the Bush Wren (Xenicus longipcs) — which has put off its 

 green plumage for the dun-coloured dress more in harmony 

 with its surroundings among the rocks on the open mountain, 

 and has acquired a longer hind claw, so as to fit it for this 

 different habitat — or vice versa ? The particular direction of 

 the development does not of course affect the argument. And 

 it is a significant circumstance that I possess intermediate 

 forms ; so much so, in fact, that I have been in doubt as to 

 which of the two species they really belonged. Or, to take 

 just one more case : who can doubt that the fleshy membrane 

 on the bill of our Blue Mountain Duck (Hymcnolcemus malaco- 

 rhynchus) has been specially developed to enable it to hunt the 

 more successfully for the peculiar stone-encased caddis-worm 

 of our mountain streams, which now forms its principal article 

 of food? 



But now, to revert to my main line of argument : In con- 

 sidering the problem of representative species in the North 

 and South Islands respectively, it must be borne in mind that 

 there are probably many broken links in the chain of succes- 

 sion through the disappearance of representative forms. We 

 all know that the existing avifauna is being stamped out and 

 destroyed by a variety of artificial causes, not the least 

 among them being the naturalization of foreign birds by way 

 of acclimatization, on the one hand, and the introduction of 

 bloodthirsty animals like stoats, weasels, and ferrets, on the 

 other. But long before the effects of our drastic coloniza- 

 tion made themselves felt, many of the ground species w r ere- 

 dying out, in obedience, no doubt, to that inscrutable law 

 of nature whereby races of animals and plants, apparently of 

 their own accord, die out and give place to other forms of life. 

 I remember, when I was a boy, the interest with which I 

 followed the Maoris' descriptions of birds that had even then- 

 become rare or were disappearing from the land. One bird, a 

 species of Bail apparently, was often mentioned to me under 

 the name of Pukunui — so called from the abnormal size of its 

 stomach. It was described as a reddish bird, frequenting; 

 swamps and marshes, and I was constantly hearing of it. 

 Indeed, I never made an excursion among the Maoris any- 

 where without making diligent inquiry for the Pukunui, so 

 much so that the older men thought I had Pukunui on the 

 brain. I offered liberal rewards, and often felt that the bird 

 was almost within my grasp. At length, at the small bush 

 settlement of Mareikura, on the North Wairoa Biver, one was 

 caught at the edge of a raupo swamp near the village by my 

 trusty lieutenant, Tamati Nui. It had been taken unhurt, 



