314 Prof. Dr. G. Pfeffer on the Mutual Relations 



Tn 1896 Sir John Murray published a very minute investi- 

 gation into the distribution of all the species occurring in tlie 

 Kerguelen region, and his results agree entirely with mine. 

 On that occasion he also collected the remarks of various 

 ^^Titers on this subject, and showed how strongly the likeness 

 between the forms of the higher southern and highernorthern 

 latitudes has impressed many. 



On the publication of the ' Ergebnisse der Magelhaensischen 

 Sammelreise ' the editors expressed their sense of the import- 

 ance of this point by the request that every worker at a group 

 should take account of its arctic-antarctic relations. Schau- 

 dinn and Eomer expressed the same wish in the programme 

 for the publication of the results of their Spitzbergen expe- 

 dition. 



The papers which appeared in the ' Ergebnisse der Magel- 

 haensischen Sammelreise ' and in the publication of the 

 results of Plate, Nordenskiold, and some others on the animals 

 of higher southern latitudes have not altered in its essential 

 features the picture which I sketched in 1890. The same 

 holds true of other hitherto unpublished investigations, which 

 have been communicated to me verbally, and, further, of ray 

 own work, which for some time has never been interrupted, 

 on the rich material of the Hamburg Museum, which every 

 year receives new and important contributions from the 

 southern point of South America. One thing can be affirmed 

 with decision — that the theory of the great similarity of the 

 faunas of higher northern and southern latitudes receives new 

 support from the working out of nearly all groups; and the 

 accord between the two taunas extends to hundreds of genera. 



Of the genera which occur as members both of the arctic- 

 boreal and subantarctic-notal faunas, a number are found 

 within the equatorial regions either in the surface- or subsurface- 

 water, but a considerable number are absent from this region. 

 Of the numerous species occurring both in the higher northern 

 and southern latitudes, on the other hand, only a few are 

 distributed through the tropics. In my paper of 1890 I have 

 called those species and genera which are absent from the 

 equinoctial zone, and which, owing to the discontinuity of 

 their representation, especially demand explanation, " bi- 

 polar," and their mode of distribution " bipolarity." 



Let us now return to a point which we reached earlier in 

 our study — namely, that palajontological records show a 

 great accord between the Early and Middle Tertiary of 

 Central Europe on the one hand, and of South Australia 

 and the great Australian islands on the other. This simi- 

 larity extends, among Mollusca probably, among Bryozoa 



