314 Prof. Dr. G. Pfeffer on the Mutual Relations 
In 1896 Sir John Murray published a very minute investi- 
gation into the distribution of all the species occurring in the 
Kerguelen region, and his results agree entirely with mine. 
On that occasion he also collected the remarks of various 
writers on this subject, and showed how strongly the likeness 
between the forms of the higher southern and higher northern 
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 Rémer 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, Nordenskidld, 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holds true of other hitherto unpublished investigations, which 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 my 
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 faunas 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 [ 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 paleontological records show a 
great accord between the Karly and Middle Tertiary ot 
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 
