of the Arctic and the Antarctic Faunas. 313 
Further, the supporters of the theory of the permanency of 
climatic faunas must remember that it is plainly irreconcil- 
able with the modern doctrine of evolution. If the individual 
climatic faunas had developed each for itself from the very 
beginning of the world, the types, wherever arising, could 
never have spread over the whole earth ; each faunistic region 
would have had its own phylogenetic history from the oldest 
pre-Cambrian times till now. This, however, does not accord 
with any paleontological picture whatever, nor with that 
afforded by recent zoology and botany. 
We have hitherto based the theory of the universal cha- 
racter of the Karly Tertiary fauna on paleontological data, 
and on the relations of that fauna to the present tropical surface- 
water fauna. We now come to a third consideration. 
BIPOLARITY. 
Nearly all authors who have worked at the fauna of the 
higher southern latitudes speak of the great ‘“ habit-resem- 
blance ” of this fauna to that of the higher northern latitudes. 
This likeness is, however, impaired by the fact that the 
South-American and Australian faunas send their southern 
stiagglers into these regions; further, the extraordinarily 
slight development of circumpolarity renders the presentment 
of a complete picture of the fauna asa zonally disposed whole 
extremely difficult; and, lastly, we know nothing of the 
fauna of the real antarctic. 
In the year 1890 I attempted a sketch of the surface-water 
fauna of the higher southern latitudes compared with that of 
the higher northern latitudes, which, apart from the errors 
and inaccuracies involved in statistics of that nature, presents 
a fairly complete picture of the scientific data at that time, for 
it is based on the collected literature and on the works of 
authoritative writers. 
This work brings out two points which are of essential 
importance in judging of the resemblances—first, the resem- 
blances in the various divisions of the animal kingdom are 
very unequally expressed, being in some cases quite sur- 
prising and in others hardly noticeable ; secondly, even the 
absence of many families and genera distributed over the 
warmer seas contributes to increase the habit-resemblance of 
the two faunas of the higher latitudes. For the theory we 
are now occupied with, that all the climatic faunas have arisen 
from a separating-out of the Karly Tertiary or pre-Tertiary 
fauna—that is, through a kind of selection—a negative 
resemblance is quite as important as a positive one, though it 
is less evident. 
