ANIMAL LIFE 185 



on the pelagic deposits farther removed 

 from the land ; hauls with the trawl are almost 

 always more productive than those with the 

 dredge. 



The forms recorded from the twenty-five 

 " Challenger " hauls in depths exceeding 2500 

 fathoms (referred to in the table) include 

 sponges, antipathids, actinians, corals, hy- 

 droids, crinoids, asterids, ophiurids, echinids, 

 holothurians, annelids, cirripeds, pycnogonids, 

 lamellibranchs, scaphopods, gasteropods, 

 bryozoans, brachiopods, and tunicates (in 

 addition to crustaceans and fishes, which 

 cannot with certainty be regarded as having 

 lived at the bottom, although it is believed 

 that most of the Macruridae are bottom fishes). 



The majority of these deep-sea forms live 

 by eating the superficial layers of the deposits, 

 and by picking up the small organisms or 

 organic particles falling from the surface, the 

 struggle for food being apparently nearly as 

 severe in the deep as in the shallow waters of 

 the ocean. The idea that a universal and 

 peculiar fauna of great antiquity overspreads 

 the deep ocean-floor has not been supported 

 by systematic investigations in deep water. 

 Many deep-sea species are of gigantic size 

 compared with their shallow- water allies ; 

 those living in very deep water far from land 

 present archaic characters, but the relict 



