664 PATAGONIAN EXPEDITIONS I ZOOLOGY. 



from a general Antarctic fauna, which has developed some peculiar local 

 types ; a few elements of it (Elminius, Edotia, Eurypodius] seem to be 

 altogether peculiar to these parts, while a few others belong to different 

 sources ; some immigrated from the north, and others are cosmopolitan 

 forms, the original home of which cannot be traced. No indications of 

 bipolarity are found, that is to say, 'in no case are the affinities of any of 

 these Antarctic forms to Arctic forms closer than to any other region of 

 the earth. 



This points distinctly to the former existence of an Antarctic fauna 

 peculiar to the shores of the supposed old Antarctic continent, of which 

 fauna the Magellanian is a slightly modified offshoot, blended with a few 

 types of different, presumably northern, origin and the view is supported 

 that the Antarctic fauna, in its origin, is totally different from the Arctic. 1 



With regard to the fresh-water fauna we may make the following 

 remarks. 



Most of the species recorded here belong to the class of those small 

 fresh-water organisms, for which exceptional means of dispersal (passive 

 transport by wind, water-fowl, etc.) are admissible, and even observed, so 

 that a more or less cosmopolitan distribution is not astonishing. Although 

 most of the species (except Daphnia hastata] are peculiar to Patagonia, 

 the genera are universally distributed. 



A very remarkable exception to this is presented by the Copepod genus 

 Pseudobczckella. The distribution of this and the allied genera (Boeckella, 

 Bceckellopsis, Parabwckelld] is almost exclusively restricted to the Antarc- 

 tic countries (only in S. America the range extends into Brazil). I give 

 here a synopsis of the known localities, following Mrazek's (1901) classi- 

 fication. 



The genus Backella (typ.) Mraz. contains three species from Australia 

 and New Zealand (B. triarticulata (Thorns), minuta Sars, robusta Sars). 

 To these we have possibly to add : B. gracilipes Dad., gracilis (Dad.) and 

 pygmcza Dad., from Patagonia and Chili. 2 



Pseudobceckella Mraz. contains the following species : brasiliensis (Lubb.), 

 Patagonia and Brazil; poppei Mraz., S. Georgia and S. Patagonia; longi- 

 cauda (Dad.) and entzi (Dad.) both from Patagonia ; and probably also : 

 dubia (Dad.) and sihestrii (Dad.) from Patagonia. 



'See Ortmann in Proc. Americ. Philosoph. Soc., v. 41, 1902, p. 399, footnotes. 

 2 Daday in Term. Fiiz., v. 25, 1902, p. 444. 



