f)l<S REPOKT OF COMMISSIONER OF FISH AND FISHERIES. 



also the deeper zoiiaiy le.yions. For in tlie tro])ical zone there are 

 iniineroiis iiyctipehii;ie oigaiiisnis, Avhi(;li by day shun the glow of the 

 per])en(licular rays of tlie sun and betake tliemselves into the cooler, 

 more or less deep layers of water; but at night these bathypelagic ani- 

 mals and plants appear at the surface in such immense crowds that 

 they arc not suri)assed in quantity by the "immeasurable swarms" of 

 pelagic organisms in the temperate and cold zones. 



During my trip tbrougli the trojiical region of the Indian Ocean, as 

 well on the way to Ceylon (from Bombay) as on the return (froni Soco- 

 tora), I daily Avondered at the great richness of pelagic life on the mir- 

 rored surface. At niglit the "\vhole ocean, as far as the eye could see, 

 was a continuous shimmering sea of light" (25, p. 52). The luminous 

 water, which at night we scooped up directly from the surface with 

 buckets, showed a confused mass of nyctipelagic luminous animals {Os- 

 tracods, Salpa, Pyrosoma, Mediisw, Pyrocyst(c), so closely packed that 

 in a dark night Ave could plainly read the print in a book by the bright- 

 ness of their pelagic light. The crowded mass of individuals was not less 

 considerable than I have so often found in the Mediterranean in the 

 currents of Messina. What quantities of food the plankton must here 

 furnish to the larger animals was shown by the vast schools of great 

 medusoe and flying-lish, which for days accompanied our vessel; and 

 this mass covered large areas of the open Indian Ocean, midway 

 between Aden and Ceylon. Just such plankton masses I have received 

 through the kindness of Capt. Rabbe from other tropical parts of the 

 Indian Ocean, between Madagascar and the Cocos Islands, and be- 

 tween these and the Sunda Archipelago. I encountered a wonderfully 

 rich and thick planlctonic mass in a pelagic current of the southwest 

 monsoon drift, 50 nautical miles south of Dondra Head, the southern 

 point of Ceylon.* I have referred to the richness of this in my "Indian 

 Journal" (25, p. 275). 



That the tropical zone of the Atlantic Ocean also possesses a vast 

 wealth of plankton is shown by many older accounts, but especially 

 from the experience of the ('haUen<fcr. In the middle of the Atlantic, 

 between Cape Verde and Brazil, Murray observed colossal masses of 

 pelagic animals; and if by day they were scarce at the surface, he con- 

 tinually found tliem below the surface, in depths of 50 to 100 fathoms 

 and more (0, p}). 105, 218, 270, etc.); at niglit they ascended to the sur- 

 face and filled the sea far and wide with a brilliant glow (pp. 170, 195, 

 etc.). " On the whole cruise alonrj the Guinea and enualorial currents, the 

 pelagic life was exceedingly rich and varied, in the (piantities of individ- 

 uals as well as of species, much more than anywhere else in the northern 

 or southern ])art of the Atlantic Ocean. The greatest quantities were 

 seen in theCuinea current during calms, ivhen the sea. literally swarmed 



*A ])art of the new spooies of ju'lnnjic aiiinials whicli 1 foinul in this .astonishingly 

 riih oc«ninic onncnt are (Icsftrilud in my '• I\ci)oits on tlic Siiihoiiophora and Radio- 

 laria of H. M. S. CliaUoiffer." 



