250 
THE VOYAGE OF H.M.S. CHALLENGER. 
The Challenger’s dredging and trawling operations have shown that, not only in 
shallower water near coasts, hut even in all the greater depths of all oceans, animal life is 
exceedingly abundant. A trawling in a depth of over a mile (1000 fathoms. Station 78) 
yielded two hundred specimens of animals, belonging to seventy-nine species and fifty -five 
genera. From a depth of about two miles (1600 fathoms. Station 147) a single haul of 
the trawl procured over two hundred specimens of deep-sea animals, belonging to 
eight}^-four species and seventy-five genera. A trawling in a depth of about three miles 
(2600 fathoms. Station 160) yielded over fifty specimens, belonging to twenty-seven 
species and twenty-five genera. These are but a few, and not the most striking, of the 
examples that might be cited. From the contents of their stomachs it was evident 
that the great majority of these lived on, or in the immediate neighbourhood of, the 
bottom. Even in depths of four miles, fishes and animals belonging to all the chief 
invertebrate groups have been procured, and in the sample of ooze from nearly five 
and a quarter miles (4475 fathoms) there was evidence that living creatures could exist 
at that depth. In the deeper waters far removed from the coasts the genera and 
species are almost all new to science, while at similar depths near continents the species 
and genera are both more numerous, and include many more forms identical with, or 
closely allied to, shallow-water species. These results have been confirmed by subsequent 
investigations in special regions by French, German, Italian, Norwegian, and British 
expeditions. 
Haeckel has introduced the useful term “ Benthos” to designate all those animals and 
plants li\’ing fixed to, or creeping over, the bottom of the ocean, and in accordance with 
the classification given on pages 185 and 186 we would propose that the Benthos be 
divided into neritic Benthos and deep-sea Benthos. The neritic Benthos may be sub- 
divided into littoral Benthos and shallow-w^ater Benthos. The deep-sea Benthos may 
again be sulxlivided into bathybial Benthos for those animals living on deep-sea terri- 
genous deposits, and abyssal Benthos for those living on pelagic deposits. 
Not only is life everywhere distributed over the floor of the ocean, but experiments 
appear to show that it is present everywhere throughout the whole body of oceanic waters 
at all depths from the surface to the bottom, most abundant at and near the bottom and 
at and near the surface, while much more sparingly represented in the waters of inter- 
mediate depths. In the spring of 1891, Alexander Agassiz conducted experiments with 
closing tow-nets from the U.S.S. “ Albatross,” off the Pacific coast of America. At 
intermediate depths greater than 200 fathoms he did not procure any animals in the 
open ocean, but a few specimens were obtained from these intermediate waters in the 
Gulf of California.* As all the surface animals must after death fall towards the bottom, 
we should ex[>ect to ca[)ture such specimens, at least sparingly, in tow-nets dragged at 
intermediate depths, and such captures seemed to be clearly indicated in the Challenger 
‘ Hull. Miu. Comp. ZooL, vol. xxi. pp. 186-200, June 1891. 
