158 J. MURRAY 



discovered by liichters in Samoa, and E. arctomys, recorded by him for Oahu, we 

 have 17 species known from the Pacific Islands. 



The only instance of a species known to be common to two islands is M, hufelandii 

 in Oahu and Hawaii. This fact is of no importance, as only Oahu is at all well 

 known. 



There are 7 species of Echiniscus (besides 1 not identified) all from Oahu. No 

 Echiniscus is known in the other islands. There are 8 identified species of Macro- 

 biotus, 5 from Oahu, 2 from Fiji, and 1 from Samoa, the ubiquitous Milnesium, and 

 Diphascon scoticum. 



There are eight of the species which are almost cosmopolitan in distribution, and 

 which are therefore of little importance in the study of island faunas. They indicate 

 that migration to these remote islands is not difficult. 



The other nine species are of very restricted range. None of them is known in 

 more than three of the regions, though only M. samoanus is confined to the islands. 

 E. novcezeelandiai occurs in Oahu, Australia, and New Zealand ; E. intermedius 

 in Oahu, Australia, and Canada ; E. viridis in Oahu and Scotland ; E. spinulosus in 

 Oahu, Europe, and the Arctic ; E. perarmatus in Oahu and Africa ; M. occidentals 

 in Oahu, Australia, and Canada ; M. crassidens in Oahu, Australia, and Africa ; 

 M. nodosus in Fiji, New Zealand, and Africa. 



The proportion of the island species found in other countries is as follows : Of the 

 17 species, there are 11 in Australia, 10 in Europe and Africa, 9 in the Arctic, 8 

 in N. America, 7 in New Zealand and Asia, 5 in S. America, and 4 in the Antarctic. 



While the indicated affinity is closest with Australia, it is scarcely less with the 

 distant Europe and Africa. The presence of so many species in common with such 

 diverse and distant lands, and the scarcity of peculiar species, show the population of 

 these islands to be a heterogeneous lot, recruited by casual immigration from all sorts 

 of places. 



Our information is too scanty to allow of even this conclusion being made with 

 any confidence, as it is quite possible that further work may bring to light a peculiar 

 insular fauna of water-bears. At present there is no indication of such, except the 

 solitary M. samoanus. 



