254 SUBANTARCTIC ISLANDS OF NEW ZEALAND. [Oligochaeta. 



Plngiochneta, represented by a single species on the Aucklands, is peculiar to 

 New Zealand, and hitherto has not been found in the North Island ; in the South 

 Island it is represented by several species, from Nelson to Invercargill and from 

 the east coast to the west ; and it also occurs on Stewart Island. 



The occurrence, then, of these three genera evidently indicates a former land 

 continuity between the mainland and these subantarctic islands. 



Notiodrilus {s.l.) is a genus which is found in New Zealand and its southern 

 outliers, as well as at Kerguelen, Marion Island, the Crozets, South Georgia, Falk- 

 land Islands, Patagonia, Tierra del Fuego, and Cape of Good Hope — in other words, 

 it is circumpolar — and to its importance I have already called attention in my address 

 to Section D at the meeting of the Australasian Association for the Advancement of 

 Science, at Hobart, 1902. It may be remarked, however, that further research 

 has shown that the genus occurs elsewhere, as in Mexico, Madagascar, Guatemala, 

 Cameroon, and north-west Australia. I have some remarks on this matter under 

 the account of N. fallax. Three species of this genus were already known from these 

 subantarctic islands of New Zealand, and I now add a fourth from the Snares. 



The genus Phreodrilus is characteristically Antarctic, with nine hitherto-described 

 species ; it is represented in New Zealand by at least three — perhaps four — species, 

 the remaining species occurring on Kerguelen, Crozets, Falkland Islands, and Tierra 

 del Fuego. The majority of the species are found on the sea-shore. 



Although this subantarctic distribution of Notiodrilus and Phreodrilus seems 

 to be best explained by the supposition of a larger tract of land in these regions, 

 as was first indicated by Beddard and later dealt with by me at some length in 1902, 

 yet the leading authority on Oligochaeta is entirely opposed to this suggestion. 

 Michaelsen, in 1902, and again in 1907, having noted that many of the species of 

 Notiodrilus (and of some others) can and do live on the sea-shore, and, using the term 

 " euryhaline " to express this mode of life, says, " Through their euryhaline nature 

 one easily explains this wide distribution of the genus across the seas, which in 

 consequence of the ' West-wind Trift ' — a current present in the circumpolar sub- 

 antarctic seas — can be carried from station to station, and thus come to have a 

 circumpolar distribution" (1907, a, p. 144). He supposes that the worms or their 

 cocoons may be carried in seaweed from island to island. Any one who has had 

 experience of the size and tremendous power of the waves in these southern lati- 

 tudes, and of the terrific wind-storms that constantly rage over these seas, will be 

 in a position to recognise the high degree of improbability that seaweed could be 

 carried from island to island by the " West-wind Trift " without being torn into 

 fragments. Oligochaeta or their cocoons would soon be wrenched from the plant, 

 and their arrival at any distant land-surface — say, from Marion Island to Kerguelen 

 — is, in my opinion, quite outside the realm of probability. When I stood at the 

 top of the sheer cliffs, some. 500 ft. to 1,000 ft. in height, which form the whole of 

 the west coast of Auckland Island, and saw the tremendous breakers which even 

 in moderately calm weather dash with incredible force against the rocks, I was 

 more than ever convinced that the " West-wind Trift " cannot account for the 

 transference of Oligochaeta from the various land-surfaces of this subantarctic region. 

 It is also extremely likely that the worms would fall a prey to fishes, or be engulphed 

 by whales while feeding, long ere they would reach another land-surface. Even if 

 it be within the bounds of possibility to explain the distribution of Notiodrilus and 



