PRELIMINARY REPORT. 89 
All we may assert at present is that there is a great intertropical belt ex- 
tending north and south of the equator twenty or twenty-five degrees of 
latitude and reaching from the Central American district west, as far as the 
East Indian Archipelago. The surface fauna of this extensive area is quite 
uniform and has a wide geographical range in longitude ; while both north 
and south of it we have the temperate surface fauna, which in latitude passes 
gradually into a subarctic and subantarctic fauna. The tropical fauna is 
characterized by the greater number of genera and species and the small 
number of individuals of each. As we proceed north or south into the 
temperate or subarctic and subantarctic regions the diversity of the fauna 
shows a marked diminution in the number of genera and species, with a 
corresponding increase in the number of individuals of the species charac- 
teristic of the temperate and of the more northern or southern belts. As 
regards the correlation of the fauna of these different regions in depth and 
in latitude, the material available for such a comparison has not yet been 
sufficiently worked up. 
Hauls made at intermediate depths by the “ Albatross.” 
To supplement the surface hauls the open tow-nets were sent to tow 
at depths varying from 100 to 400 fathoms, and after having dragged 
at certain depths they were run up to the surface open, thus mixing 
the materials which might have been obtained at different depths by 
closing-nets. One cannot fail to be struck with the fact that the nets sent 
down to these greater depths did only in very few instances collect any 
forms which might be said to live in intermediate depths, as compared with 
those collected in the surface hauls. 
At the following stations hauls with the open tow-net (unless otherwise 
stated) were made by the “ Albatross” at definite depths for a limited time, 
then the open tow-net was dragged to the surface. The legend is as 
follows, viz.: Station 1. At 300 fathoms and to surface; meaning that the 
open tow-net was dragged at a depth of 300 fathoms generally twenty to 
twenty-five minutes, and then dragged to the surface and contents of net 
examined. Other stations have a corresponding legend. The net was 
kept practically at the depth indicated by means of the clinometer in use 
on the “ Albatross.” 
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AR teen ee a gf ne te 
