78 Capl. F. W. Hutton on the Origin of the 



than at present ; but I had to postpone the proof of the Plio- 

 cene upheaval. We now come to the consideration of the 

 two remaining- elements — the antarctic and the north-tempe- 

 rate — and we have to inquire at what time they came. 



The antarctic element, as we shall presently see, must have 

 invaded New Zealand from the south. It consists of plants, 

 sea-birds, freshwater fishes, marine fishes, marine Crustacea, 

 and marine shells. There are also a few insects, such as the 

 beetles Heterodactylus and Pristancylus of the Auckland 

 Islands, but no land birds or land Mollusca. A very large 

 portion of the north-temperate element no doubt came with 

 the antarctic forms ; for, as we saw in my last address, the 

 percentage of endemic species of plants belonging to each 

 element is almost identical. These probably travelled to the 

 southern hemisphere by the chain of the Andes, and then 

 spread with the Fuegian plants. But several of our plants, 

 insects, and arachnids are allied to northern forms, and have 

 no near relations in South America. These probably migrated 

 to us direct by the mountains of the Indian archipelago at 

 the same time that we were invaded by the Australian and 

 Polynesian floras. This latter portion I shall leave out of 

 consideration, and shall confine my attention solely to the 

 invasion from the south by both the antarctic and north-tem- 

 perate elements. 



Now in dealing with this part of our fauna and flora we 

 have to take into consideration two means of dispersal, at 

 present going on, which are not found, or only to a very 

 limited extent, in the tropical parts of the ocean. In the first 

 place the almost constant westerly winds travelling round the 

 globe in high southern latitudes cause an easterly current 

 which must necessarily drift to great distances the detached 

 masses of kelp which are commonly seen floating in these 

 seas, and the kelp might easily convey marine Crustacea and 

 Mollusca with it. In the second place the larger petrels 

 range widely over the southern ocean, and might sometimes 

 carry seeds in their plumage. I leave icebergs out of con- 

 sideration, for they would not assist marine animals in 

 migrating, and I do not see how any of our insects or fresh- 

 water fishes or the seeds of any of our flowering plants could 

 get upon them. Capt. Cook thus describes the vegetation of 

 South Georgia, between lats. 54° and 55° S. : — " Not a tree 

 was to be seen, not a shrub even big enough to make a tooth- 

 pick. The only vegetation we met with was a coarse strong- 

 bladed grass, growing in tufts, wild burnet, and a plant like 

 moss, which sprang from the rocks " *. No flowering plant 

 * ' Voyage round the World, 1772-75/ vol. ii. p. 213. 



