4F Canadian Arctic Expedition, 1913-18 
Bering strait, while the: wider channel between Greenland and Spitsbergen 
serves mainly for a southward moving outflow. The Antarctic, on the other 
hand, has no such barriers interposed between it and the rest of the watery 
world. If one consults a chart of the great sea currents it will be readily seen 
how free is the interchange between the Antarctic sea and the vast ocean areas 
of the world, and how restricted the interchange between these 4nd the waters 
of the Arctic. Now, it is at least possible that the narrowness of these water- 
ways linking the Arctic with the rest of the world constitutes a barrier to the 
introduction of new forms of marine life from other regions, among which new 
forms there might well be now and then species adaptable to the rigorous life 
conditions of polar waters and which would thus add to the richness of its local 
flora and fauna. For such introductions, multiplied and continued through 
long agés, would have no inconsiderable influence in this respect. And as the 
Antarctic sea does lie open to such importations, it is not to be wondered at that 
we find there, as we do find, a much richer diversity of diatoms, some of them 
perhaps locally evolved and some immigrants from other regions. 
It would be a mistake to conclude from the foregoing that diatoms find an 
uncongenial home in the Arctic region. Although simplicity of structure and 
low number of species are characteristic of that locality the diatoms that do 
grow there flourish amazingly; so that in the matter of quantity few regions 
are as prolific of diatoms as the Arctic. Dr. Nansen and other explorers of the 
North Polar seas have recorded the unusually rich dredgings of diatom ooze 
secured there. The species adapted to a life in those frigid waters, with their 
long winters, of night, are indeed few; but the fecundity of those that do grow 
there probably surpasses anything to be found in temperate or tropical regions. 
And in this respect any difference between Arctic and Antarctic diatoms wholly 
disappears; for in the Antarctic also the richness of the diatom ooze is start- 
ling and will impress anyone familiar only with material coming from tempe- 
rate or tropical waters. This fact is deserving of the attention of all ecologists, 
because it is closely linked with the abundance of animal life inhabiting the 
northern and southern polar seas. 
There will be found following each species in the list of diatoms here re- 
corded one or more references to diatom literature. These have been so selected 
as to give the best descriptions and especially the best illustrations of the species 
in question; or in a few instances they refer to some figure which most accurately 
depicts that particular variation from the type form which is the one here dis- 
covered. This selection of references is necessary in fixing the forms here re- 
corded because many figures in diatom publications are misnamed or, even 
more important, are so minute or so unreal in their markings as to be worthless. 
‘This is particularly true of illustrations made by early diatomists, to whom a 
sketchy suggestion of the diatom they were recording seemed to be quite satis- 
factory if it distinguished it from the comparatively few forms then known to 
the science. In consequence we find that to-day many of the figures and des- 
criptions in these old works have become utterly valueless for purposes of 
identification, as for example, Ehrenberg, Agardh, Kiitzing, Nitzsch, ete. 
However, out of the most of these old named forms there have grown up quite 
definite concepts, the modern idea of the species; and it is to these later, sharply 
distinctive illustrations and descriptions that reference is here made. 
In publications more modern than the foregoing we find much deplorable 
confusion introduced into diatom taxonomy because some authors have, on the 
one hand, assigned to the same species wholly different diatoms, or, on the other 
hand, have given new names to species already fixed. This has come about part- 
ly through carelessness but chiefly because of the rarity of so many important 
diatom publications. As the writer enjoys the advantage of being able to con- 
sult practically every work of value on this subject it seems worth while to correct 
in this paper some of these blunders by referring the reader, as above stated, 
