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proof of the inadequacy of our knowledge; and the important 
theoretical consequences that would follow from proof of the fact, 
or indeed from any other relation that could he clearly demon- 
strated between the polar faunae and specific lines or areas of 
distribution in the other oceans, exemplify on the zoological side 
the magnitude of the general problems that deep-sea exploration 
has yet to solve. 
But we are impatient to know, and we are tempted, even in the 
absence of definite or adequate knowledge, to discuss, how far this 
Antarctic faunae extends into other seas, to what degree it is 
kindred to the marine fauna of the north, how temperature, ocean- 
current, or other causes may distribute or circumscribe it, and 
whether existing phenomena are adequate, or past conditions of the 
globe are necessary, to account for the facts we find. I, for my 
part, hold with Ortmann, that an actual community of forms is not 
proven, save for a very few forms, some peculiar to the extreme 
depths of the sea, and others that inhabit the surface of the ocean 
in colder latitudes while represented in the deeper and colder 
waters of tropical seas ; and I hold with Chun that the necessity 
has not been shown for invoking, in explanation of such community 
and intermixture of forms as actually exists, the hypothesis of a 
remote community of origin under different conditions in pre- 
tertiary times. 
Sir John Murray has given in his paper, “On the Deep and 
Shallow Water Marine Fauna of the Kerguelen Region of the great 
Southern Ocean ” (Trans, Roy. Soc. Edm ., xxxviii., 1895), a list 
of nearly one hundred species of animals that are recorded as 
identical from northern and southern waters, though absent from 
tropical seas. Had we anything like so great a list to deal with of 
well-marked and unmistakably identical forms, the case would be 
indeed a remarkable one. But though Sir John Murray has 
shown that the forms tabulated in his list were sometimes recorded 
not as identical but as distinct varieties, and that in other cases the 
identification was admittedly dubious, I do not think that he has 
at all fully allowed for the extent to which the basis of his theory 
is weakened by the aggregate of dubiety in these and other 
individual cases. I think that we should be very reluctant indeed 
to rest so weighty a conclusion on facts drawn from fragmentary 
