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PELAGIC FAUNA 



nounced in crustaceans, where they take the form of long feelers, spines, 

 or bristles, which may even be feathery. Notable in shallow water are the 

 many larvae of crabs and other bottom-living crustaceans. A few annelid 

 worms are adapted to pelagic life entirely, including the genus Tomopteris, 

 which has no bristles but outspread parapodia and long feelers. Pelagic 

 molluscs, especially pteropods and heteropods, have very thin and light 

 shells. Globules of oil are found in some crustaceans (copepods) and in fish 

 eggs, as also in some of the siphonophores, though others remain buoyant 

 by means af air bladders. Finally, many animals have their specific gravity 

 in relation to water much reduced by body walls which are thick and 

 watery, that is to say, gelatinous. This especially applies to the salps, the 

 beautifully luminescent pyrosomas, most jellyfish, and some of the micro- 

 scopic protoza. Several different methods of flotation may sometimes be 

 present in the same animal. 



Every opportunity was taken to obtain samples of plankton. As each 

 of our numerous samples contained representatives of nearly every group 

 of pelagic fauna, it is obvious that only a minute proportion could be 

 closely studied on board; for that the cooperation of a number of spe- 

 cialists is required. But when I was on board, between Mombasa and the 

 Torres Strait, close attention was given to jellyfishes and whenever I had 

 the opportunity I studied previous catches. We had a rich haul. 



Suspending the silk-net over the 

 side so that small animals will 

 drift into it with the current while 

 the ship is stationary. 



