Surface Fauna of the Bay of Fundy. 611 
the cold polar seas, as far as temperature of the water goes, is 
greater than under the equator at the surface.. Consider the waters 
of the polar ocean covered by a paleocrystal ice, and those unpro- 
tected under the burning tropical sun. In the one there is certainly 
a minimum of variation in temperature, in the other a maximum, 
as far as the water is concerned. If environment, if uniformity of 
conditions, has anything to do with variation in forms of life or 
with the preservation of ancestral features through long periods of 
time, should it not appear in the animals which live under these 
conditions ? 
There is a certain parallelism in the animals of cold and warm 
oceans and those of deep seas and littoral zones. It is, of course, 
impossible to link together what we know of deep-sea life with 
that of the polar region with any hope of a satisfactory answer as 
long as our knowledge of either is incomplete. Fortunately the 
character of deep-sea life in late years has been investigated. As far 
as this problem goes, the least satisfactory part is that which pertains 
tothe nomadic deep-sea genera. With regard to the marine life of the 
polar regions, where the deep-sea temperatures become surface tem- 
peratures, much remains to be done. We know the littoral marine 
Invertebrata of the polar sea better than those of many bays con- 
tiguous to our own eountry, but the subject of the marine surface 
fauna is yet to be more fully investigated. If polar exploration is 
to be continued, as there is no doubt that it will be, a more com- 
plete study of the marine life would be an important object of such 
exploration, and would be of value to our knowledge of the geo- 
graphical distribution of marine animals. It would be interesting 
to take up again the somewhat threadbare discussion of a relation- 
ship between the Arctic and deep-sea faunae. It might verify a 
prediction that it is possible to recognize ancestral forms among those 
Which people the icy waters of the polar seas. The theory of the 
Arctic character of deep-sea faunæ is by no means a new one, and as 
long as the zone of deep water from 100 to 300 fathoms was studied 
there seemed to bea marked likeness between these two fauna. When, 
however, the variegated fauna of the abysses of the ocean came to be 
studied, it became more difficult to found resemblances between deep- 
Sea animals and those of the poles. Our comparison of deep-sea 
floating life with the polar introduces a new phase in the discussion, 
