NEW ZEALAND. 



449 



— It has been well observed by Captain Hutton, in his inter- 

 esting paper already referred to, that the occurrence of such a 

 number of species of Struthious birds living together in so 

 small a country as New Zealand is altogether unparalleled else- 

 Avhere on the globe. This is even more remarkable when we 

 consider that the species are not equally divided between the 

 two islands, for remains of no less than ten out of the eleven 

 known species of Dinornis have been found in a single swamp 

 in the South Island, where also three of the species of Apteryx 

 occur. The New Zealand Struthiones, in fact, very nearly equal 

 in number those of all the rest of the world, and nowhere else 

 do more than three species occur in any one continent or island, 

 while no more than two ever occur in the same district. Thus, 

 there appear to be two closely allied species of ostriches inhabiting 

 Africa and South-western Asia respectively. South America 

 has three species of Ehea, each in a separate district. Australia 

 has an eastern and a western variety of emu, and a cassowary 

 in the north ; while eight other cassowaries are known from the 

 islands north of Australia — one from Coram, two from the Aru 

 Islands, one from Jobie, one from New Britain, and three from 

 New Guinea — but of these last one is confined to the northern 

 and another to the southern part of the island. 



This law, of the distribution of allied species in separate areas 

 — which is found to apply more or less accurately to all classes 

 of animals — is so entirely opposed to the crowding together of 

 no less than fifteen species of. wingless birds in the small area of 

 New Zealandj that the idea is at once suggested of great geogra- 

 phical changes. Captain Hutton points out that if the islands 

 from Ceram to New Britain were to become joined together, we 

 should have a large number of species of cassowary (perhaps 

 several more than are yet discovered) in one land area. If now 

 this land were gradually to be submerged, leaving a central 

 elevated region, the different species would become crowded 

 together in this portion just as the moas and kiwis were in 

 New Zealand. But we also require, at some remote epoch, a more 

 or less complete union of the islands now inhabited by the 

 separate species of cassowaries, in order that the common 

 ancestral form which afterwards became modified into these 



