204: THREE CRUISES OF THE "' BLAKE." 



whole floor of the oceanic basins, in which the lower forms only 

 needed to roll round to find all the food they could absorb. The 

 naturalists of the " Challenger," who introduced Bathybius to 

 the scientific world, were the first also gracefully to recant before 

 the overwhelming proof of its non-existence which they them- 

 selves had collected.^ But it still figures in some quarters as a 

 prominent organism, which the Haeckelian theory of the views 

 of creation demand. The younger Sars and Alphonse Milne- 

 Edwards have also found this sheet of organic matter, the nature 

 of which is certainly not Bathybius in the sense in which it is 

 understood by Haeckel. 



A number of the marine animals ultimately depend for their 

 food upon the pelagic fauna. The fishes feed upon the hosts of 

 free-swimming Crustacea, many of which develop with immense 

 rapidity ; ^ these in their turn depend for their food upon smaller 

 creatures floating in the water, and found everywhere in the 

 track of currents. There can be no better evidence of the mass 

 of food contained in the sea than is afforded by the examina- 

 tion of the contents of a tow-net any night. Pour the contents 

 into a glass jar, and note the edge of the vessel exposed to the 

 light, — it is covered with Crustacea, annelids, and mollusks ; 

 and examine also the residue at the bottom, — a true broth, con- 

 sisting of the carcasses of aU the minute shore and pelagic ani- 

 mals, and a mass of spores of all sorts of marine plants. This 

 broth is used in the Newport Laboratory to feed young fishes 

 and other embryos kept in confinement. 



Nowhere do we see the struggle for existence going on so 

 visibly as among the pelagic animals. They all prey one upon 

 the other. The acalephs swallow hosts of minute Crustacea, 

 which in their turn are filled with embryos of Crustacea smaller 

 than themselves, or with spores of algse. 



The Crustacea, large and small, form the main food supply of 

 the young fishes which dart about in search of nourishment in 



^ The naturalists of the " Challenger " ^ Qf some copepods there are no less 



showed that bathybius was only liocculent than thirty generations in three weeks ; 



precipitate of a sulphate of lime, thrown so that, with ample food and in the ab- 



dowu from salt water by organic matter sence of enemies, the progeny soon passes 



in the presence of alcohol. beyond calculation. 



