Relations of the New-ZeaJand Fauna. 35 



curious anomaly which as yet has received no explanation ; 

 and it must also be noticed that Cape Horn, the Cape of Good 

 Hope, Australia, and New Zealand possess each a black 

 oystercatcher [Hfematojms) which are considered specifically 

 distinct. 



Among the herons the only very remarkable fact is the 

 occurrence of the little bittern [Ardea 2yus{Ua)^ a bird found 

 only in Australia and Natal. Our snipe {Gallinago pusilla) 

 very much resembles in plumage G. Stricklandi from TieiTa 

 del Fuego, but it has a sliorter bill. 



Among the web-footed birds the first thing that claims our 

 attention is the oceanic family of the petrels {Procellariidce) ^ 

 for although by no means peculiar to New Zealand*, the great 

 number of species in the southern oceans in comparison with 

 the small number in the northern is very noticeable. The 

 northern and tropical species have all closely allied forms in 

 the southern hemisphere, while many of the southern petrels 

 (such as Ossifraga^ Halodronia, Majaqueus^ Pterodroma, Dap- 

 tion^ and Prion) have no representatives in the northern seas. 

 This leads to the inference that the northern species have been 

 derived from stray southern birds, and that the southern hemi- 

 sphere has been the centre from which most oceanic birds have 

 spread, while land birds, on the contrary, have spread chiefly 

 from northern areas ; and this leads to the further inference 

 that the southern hemisphere has been for many ages more 

 oceanic in character than the northern. The next most re- 

 markable point is the great development of the cormorants. 

 New Zealand possessing nine species, four of which are found 

 nowhere else. No other country in the world possesses so 

 many ; and the phenomenon can only, I think, be accounted 

 for in the same way as the numerous species of moa — that is, 

 by the former existence of several small islands which have 

 since been elevated to form the present New Zealand. The 

 wide dispersion, however, of two of our cormorants is rather 

 against this view, one [Graculus carunculatus) being found at 

 the Crozet Islands and at Cape Horn, and the other ( G. carlo) 

 in Australia, Cliina, and Europe. I must, however, remark 

 that the identity of the first has not yet been perfectly 

 established, and that the second, although very closely re- 

 sembling specimens from Europe, shows at the same time some 

 difference. It may also be useful to remark here that our 

 gannet [Dysporus serrator), although a far better-flying bird 

 than the cormorants, is not found at tiie Chatham Islands ; and 

 Dr. Finsch informs me that it is uivloubtcMlIy difl'erent from 



♦ Procellaria I'lirhiitsoni is peculiai' to New Zcalniid. 



3* 



