COLLEMBOLA— CARPENTER. 263 



in the uorthern regions. We have seen that Gomphiocephalus is akin to Achorutes 

 and to Xenylla ; Achorutes viaticus (Linn.) common in the Arctic regions and in 

 Northern Europe, is now known from Tierra del Fuego (Wahlgren, 1906) and from 

 Macquarie Island to the south of New Zealand (Carpenter, 1909), while Xenylla 

 humicola (Fab.), another arctic and northern species, has been recognised in South 

 Georgia, according to Wahlgren {I.e. p. 5), who enumerates eight species of 

 Achorutinae, referable to six different genera from various antarctic and sub-antarctic 

 localities. 



In an account of some Collembola from the South Orkneys (1906) I discussed 

 the close relationship of certain species, such as Proisotoma brucei from that archipelago 

 with arctic and northern springtails, and suggested that wingless insects with such 

 geographical relationship " at or beyond the southern limits of the present American 

 continent must be either comparatively recent immigrants — Pliocene or later — or else 

 carry us back to early Mesozoic times." Naturalists who believe in the "accidental" 

 dispersal across grea,t ocean-tracts of insects like these will possibly incline to the 

 former alternative, while those who doubt the adequacy of such modes of transit will 

 probably agree that the distribution of the Antarctic Collembola suggests the existence 

 of Mesozoic land-tracts between Antarctica and the countries to the north. It seems 

 that this latter opinion is supported by the presence on South Victoria Land of the 

 springtail described in the present paper. The locality whence it comes and its mode 

 of occurrence suggest that it is one of the few survivors of an ancient laud fauna, and 

 many lines of evidence converge to indicate a comparative richness of plant and animal 

 life on the extended Antarctica of Mesozoic and Cainozoic times, as Hedley (1912) 

 and others have shown. 



In Graham Land and on the South Orkneys, as well as in Campbell Island (south 

 of New Zealand) there are found Collembola — the genera Cryptopyyu.s and Tria- 

 canthella for example (see Wahlgren, 1906, Carpenter, 1906, 1909) — of a type distinct 

 from those Antarctic springtails which — like Gomphiocephalus and Proisotoma brucei — 

 resemble certain members of the general northern continental fauna. These genera 

 — apparently peculiar to antarctic and sub-antarctic lands — are of high interest ; 

 though possibly less ancient than their companions with a range wider and more 

 discontinuous, they appear to have become specialised within the limits of the great 

 Southern Continent of former periods. It is at least possible that the discovery of 

 some of their representatives may reward the efforts of future explorers on the 

 mainland of Antarctica. 



