236 DISCOVERY REPORTS 



present distribution of species of Microscolex in southern and sub-Antarctic islands, 

 from the South American eastwards to the New Zealand region, as a result of the former 

 existence of an Antarctic Continent with a temperate climate, with northward extensions 

 which reached and included the scattered islands of the southern seas ; while Michaelsen 

 looks on this distribution as due to the dispersal across the ocean of the genus Microscolex 

 (of which at least some species are littoral in habitat and euryhaline) from its home in the 

 south of South America by the agency of the "west wind drift". 



But it is generally recognized that the distribution of the smaller Oligochaeta (Micro- 

 drili), and especially of the freshwater and littoral genera, has little bearing on the larger 

 questions of zoogeography. They are easily transported by human or other agency or 

 by the inanimate forces of nature ; and accordingly we see, for example, Enchytraeiis 

 albidus, one of the commonest worms of Europe, widely distributed in the islands of the 

 southern seas (though apparently absent from the warmer regions of the globe). It is 

 therefore mainly for the simple purpose of completing our survey that I add here the 

 following notes on distribution. 



Of the worms brought back by the present expedition Marionina grisea, M. aestuum, 

 Lumbricilliis antarcticus, Enchytraeiis colpites, and Michaelsena monochaeta have each 

 been found only in a single locality {M. monochaeta in the same locality also by a previous 

 expedition). 



The genus Hesperodrilus (fam. Phreodrilidae), represented in the present collection 

 by an example from South Georgia which is specifically indeterminable, is known from 

 Tierra del Fuego, South Chile, South Georgia, the Crozets, Kerguelen Island, Campbell 

 Island, New Zealand, and New South Wales. 



The genus Achaeta (this and the following genera belong to the Enchytraeidae), of 

 which an indeterminable example was taken in South Georgia, is also known from 

 Europe and New Zealand. 



Marionina grisea and M. aestuum, though I consider them as specifically distinct, 

 form with M. werthi and M. benhami (cf. p. 250) a closely interrelated group, the species 

 of which stretch in a line from the Palmer Archipelago (grisea) through South Georgia 

 (aestuum) and Kerguelen (werthi) to Macquarie Island in the New Zealand region 

 (benhami), half-way round the globe. 



Marionina georgiana has been found, by the present or by previous expeditions, in 

 South Georgia, the Falkland Islands, and the Crozets. 



Lumbricilliis lineatus (a common European species) in the Palmer Archipelago, the 

 South Orkneys (between the last-mentioned locality and the next), and (with some 

 element of doubt) South Georgia, as well as in Tierra del Fuego. 



L. maximus in the Palmer Archipelago, the South Orkneys, South Georgia, the 

 Crozets, and (var. Robinson) New Amsterdam Island, in the South of the Indian 

 Ocean. 



L. macquariensis in South Georgia and in the New Zealand region (Macquarie, 

 Auckland, and Campbell Islands), but not hitherto in any of the islands between. 

 Enchytraeus albidus (common in the northern hemisphere) in Southern Patagonia, 



