610 Surface Fauna of the Bay of Fundy. 
of equal deep-sea temperature, gradually approaching the surface of 
the sea until we come to the icy waters of the pole. Here we 
should find a law of the distribution of heat similar to that which 
holds on land, where there is a constant relationship between the 
altitude above the level of the sea and the latitude as far as the 
diminution in temperature is concerned, unless modified by local 
conditions. As we ascend the tropical mountain the heat, as a general 
thing, diminishes; the same is true as we go below the ocean. As 
we increase our latitude in either case, the temperature follows a 
common law in its change, approaching pari passu the level of 
the sea. 
It was long ago recognized that the distribution of plant life on 
a tropical mountain is correlated with the change in temperature, 
and that in ascending a tropical mountain-side we pass through the 
three climati¢ zones. The author does not know how far this 
theory is now accepted by botanists, but it is interesting to see 
whether a similar law holds in the ocean where there is a like 
change in temperature. We know that there is a peculiar fauna of 
those animals which habitually live on the bottom in the deep sea. 
We know there is an sequatorial marine life which is confined to the 
surface of the ocean, represented by Physalia, Veleila, and others. 
Associated with the latter are other genera, as Afolla, which some- 
times go down to 1800 fathoms below the surface. Are there any 
meduse at 1800 fathoms which rise to the surface without destruc- 
tion? I.think there are, although our facts are not decisive 
enough to prove it.! I also believe that there are nomadic deep-sea 
animals which in the tropics cannot rise through the stratum of 
warm water above them without harm, but it by no means follows » 
that where these low temperatures of the deep seas become surface 
temperatures they may not come to the surface of the sea. 
It seems probable that the cold areas of deep seas have pre- 
served uniformity of environment for a much longer period of time 
than warmer areas of the surface. ‘The water of the ocean in differ- 
ent strata is, of course, varying its temperature, but there are 
certain positions where an almost uniform temperature has been 
kept up for long periods of time. The uniformity of conditions 12 
1 Since this was written a large number of observations by Chun 
have shown the truth of this belief. 
