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 fiir 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 surfoce 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 hi/ 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 witli the fixct 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." 



