G. M. Thomson. — On the Origin of the New Zealand Flora. 487 



Zealand and those of Soutli America, Europe, and the antarctic regions 

 respectively, and further pointing out some remarkable Pacific Island 

 peculiarities in our flora. Hooker concludes by stating that the existing 

 botanical relationships " cannot be accounted for by any theory of trans- 

 port or variation," but that they are " agreeable to the hypothesis of all 

 being members of a once more extensive flora which has been broken up by 

 geological and climatic causes." 



Leaving out of account minor speculations on this subject, we may next 

 consider the second writer named, who deals — although indirectly — with 

 the question. 



Prof. Hutton's theory*, deduced from the distribution of the struthious 

 birds in the southern hemisphere, is that there formerly existed a great 

 " antarctic continent stretching from Australia through New Zealand to 

 South America, and perhaps on to South Africa. This continent must have 

 sunk, and Australia, New Zealand, South America, and South Africa, must 

 have remained isolated from one another long enough to allow of the great 

 differences observable between the birds of each country being brought 

 about. Subsequently Nev/ Zealand must have formed part of a smaller 

 continent, not connected either with Australia or South America, over which 

 the moa roamed. This must have been followed by a long insular period, 

 ending in another continent still disconnected from Australia and South 

 America, which continent again sank, and New Zealand assumed somewhat 

 of its present form." 



It is of course assumed that this former extensive antarctic continent 

 existed at a date anterior to the first occurrence of mammals either in Aus- 

 tralia or South America, and consequently that all subsequent immigrants 

 from Australia, or from the islands lying to the north, must have found 

 their way across the intervening expanses of ocean. Professor Hutton recog- 

 nizes many of the dif&culties in the way of this theory, as, for example, the 

 occurrence of grass-birds {Sphenceacics) in both Australia and New Zealand, 

 and the existence of the genus Ocydromus (woodhens, etc.) in New Zealand, 

 Lord Howe's Island, and New Caledonia ; as the birds of both these genera 

 are almost or quite unable to fly. 



The examination of our fresh-water fish leads him to the conclusions 

 " either that our connection with Australia was later than with South 

 America, or that in the old continent New Zealand and Australia were 

 inhabited by one, and South America by another species" of the grayling 

 family. "The fresh-water fish also prove that our connection with the 



* On the Geographical Eelations of the N.Z. Fauna, by Captain F. W. Hutton. 

 " Trans. N.Z. Inst.," vol. v., p. 227. 



