ANTARCTIC ROTIFERA 61 



known species are given under eight headings, being a column for each continent, for 

 Australasia, and for the Arctic and Antarctic regions. This covers the greater part 

 of the earth's surface, only excluding oceanic islands. It may fairly be said that an 

 animal which occurs in all of these broad divisions is " generally distributed." 



Callidina habita and Adineta vaga are in every column ; C. constricta, A. gracilis, 

 and Hydatina senta are absent from one region only ; C. papillosa and A. barbata 

 from two ; A. longicornis from four ; and Diaschiza tenuior from five. These facts 

 have very little significance, as some of the regions have been very little worked. 



Considered in another way the table shows that all the previously known species 

 are also in New Zealand, all but one in Europe, all but two in Africa, N. America, 

 and the Arctic, all but four in S. America, and all but five in Asia. For the reason 

 given in the preceding paragraph these facts have no special significance. Were 

 the world more fully explored we would in all probability find that all the species 

 are ubiquitous. 



The Rotifera of the southern hemisphere, from which any migrants to the Ant- 

 arctic have most probably come, are very imperfectly known. In New Zealand 

 Hilgendorf s was the only work, and in the Index Faunae Novse-Zealandise (19) he 

 gives a list of over furty species then known. In Australia short lists were published 

 by Anderson (1) and Shephard (34 to 37), and Whitelegge (42) in 1889 summed up 

 the known species, giving a list of 110. In Africa there were short lists by Milne (24) 

 and Kirkman (22 and 23). Rousselet (33) in 1905 visited S. Africa, and in his 

 paper summarises all that was known, giving a list of 156 species. In S. America 

 Schmarda (39) found many rotifers, but his descriptions and figures are such that 

 most of the species are unrecognisable. Recently Daday wrote upon the Rotifera 

 of Patagonia (9), Chile (10), and Paraguay (11). He enumerates 106 species, 

 including some noted by Wierzejski (43). There may be isolated references to 

 rotifers of the southern hemisphere in works other than those cited, but they 

 comprise almost all that was known till recently. 



All those lists are noticeable for the very subordinate position occupied by the 

 Bdelloids. This is due to the fact that it was not suspected that mosses supported 

 a very rich fauna of rotifers and other animals. Some of the early investigators of 

 these animals, who were more interested in their physiology than in the discrimina- 

 tion of species, distinguished between the moss-dwellers and water-dwellers. 



In papers by Thompson (40) and Bryce (6) such terms as " moss-haunting" are 

 found in use, and in Germany also the word " Moosbewohner " [Richters (32)] is 

 recognised. So little was the existence of the moss-fauna known among naturalists 

 that in some of the latest expeditions the mosses were taken only as botanical 

 specimens, and were treated with preservatives which killed the fauna. 



Much work has in recent years been done on the Rotifera of all parts of the 

 globe, from specimens procured from moss. No easier method of collecting is possible 

 than by bringing home dried mosses ; and it is to be hoped that future expeditions 



