450 Ihe Scientific Advantages of an Antarctic Expedition, 



shore was known a hundred years ago, and we want to know more of 

 the undiscovered forms that are peculiar to it, and more of the struc- 

 ture and affinities of those already discovered. But apart from 

 innumerable facts appertaining to systematic or morphological 

 zoology, such as every ocean has yet to yield to us, there are certain 

 great problems of geographical distribution to which the Antarctic is 

 peculiarly likely to give a clue. Lying open to, as it were at the 

 confluence of, all the great oceans, its fauna may co-ordinate and 

 explain many things in the divergent faunas of the Indian Ocean, 

 the Atlantic, and the Pacific. One such problem Dr. Murray has 

 touched upon in his hypothesis of " bipolar distribution," that is to 

 say, of a general similarity and in many cases of actual identity 

 between the animals of the Arctic and Antarctic Seas. This theory 

 has been proclaimed before by others, by Theel, for instance, and by 

 Pfeffer; but others have contested and denied it; for instance, 

 Ortmann in regard to the Crustacea, and Chun in regard to pelagic 

 organisms. We could not have a better illustration of the poverty 

 of our knowledge than the circumstance that so broad and clear and 

 simple an issue as the existence or non-existence of a close relation be- 

 tween the Arctic and Antarctic faunas should still be open to dispute. 



For my part I think that the bipolar hypothesis is not proven, 

 and I am inclined to think it is untrue. I believe with Ortmann 

 that in the Decapod Crustacea at least one form is common to the 

 Arctic and Antarctic Seas ; and with Chun and others that there is 

 evidence that similar pelagic forms occurring in the north and south, 

 though not in the surface waters of the tropical seas, are in these 

 latter continued across the torrid zone in the deeper and cooler levels 

 of the sea. I do not think that any single fish, or any Decapod or 

 Isopod, or any certain one out of a large fauna of Amphipods known 

 from the Antarctic Ocean, is also known from the Arctic and adjacent 

 seas. It seems to me, however, that we have some good evidence of 

 very curious similarities between the marine fauna of the Antarctic 

 and that of the N". Pacific in the neighbourhood of Japan; and it 

 may be that this is to be in part explained by the existence of a line 

 of communication along the Western American coast, in waters 

 singularly cold for the latitude under w 7 hich they lie. We know 

 how, in this way, such conspicuous forms as the genus Serolis, the 

 Penguins, the Sea-elephant, the Sea-lions, and the Pur-seals, I 

 might add the giant Sea- weed Macrocystis seem to creep up the 

 American shore, from what was probably their Antarctic home, to 

 Chili, to the Gralapagos, or even to North Pacific and to Japan. But 

 these are illustrations merely of the zoological problems that Ant- 

 arctic exploration may solve. If the bipolar hypothesis be broken 

 down, it will only give place to other hypotheses as interesting as itself, 

 New facts will give rise to new hypotheses, for further facts to verify 



