5G8 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



various depths. As the most significant general result Murray, in his 

 "Preliminary Eeport" (187G), says: 



Everywhere we have found a rich organic life at and below the surface of the 

 ocean. If living individuals are scarce at the surface, below it the tow net commonly 

 discloses numerous forms, oven to a depth of 1,000 fathoms and more (5, p. 536). 



In 1875, on the journey through theKorth Pacific Ocean (from Japan 

 to the Sandwich Islands), the extremely important fact was established 

 that the i^elagic organisms in oceanic zones of difi'erent depths belong- 

 to different species; fine pelagic nets (or tow nets) " on many occasions 

 were let down even to depths of 500, 1,000, and 2,000 fathoms, and 

 thereby were discovered many swimming organisms which had never 

 been captured hitherto, either at the surface of the ocean or at slight 

 depths (up to 100 fathoms below the surface)" (0, ]). 758). The most 

 characteristic forms of these zones of different depths belong chiefly to 

 the class of the Radiolaria^ especially to the order of the Pluvodaria. 



Through the investigation of the Challenger radiolaria, which occupied 

 for ten years the greater part of my time and attention, I was led to 

 study anew these conditions of distribution; and I reached the con- 

 viction that the differences discovered by Murray in the pelagic fauna, 

 at different depths of the ocean, were still more significant than he 

 assumed, and that they had the greatest significance, not merely for 

 the radiolaria, but also for other groups of swimming oceanic organisms. 

 In 1881, in my ^^Enticurf eines Systems der Challenger Radiolarien,^^ p. 

 422, 1 distinguished three groups: («) jjelagic, living at the surface of 

 the calm sea; {h) zonary, living in distinct zones of depth (to below 

 20,000 feet) ; and {c) profound (or abyssal) animals living immediately 

 above the bottom of the deep sea. In general, the different character- 

 istic forms correspond (to below 27,000 feet) to the different zones. 



In my "General Natural History of the Radiolaria''- (4, p. 120) I have 

 established this distinction, and have expressed my conviction that it 

 is i)ossible, by the aid of a suitable bathygraphic net, to demonstrate 

 many different faunal belts overlying one another in the great deep- 

 sea zones. 



The existence of this "intermediate pelagic fauna," discovered by 

 Murray, inhabiting the zones of different depths of the ocean between 

 the surface and the deep-sea bottom, which I have briefly called " zon- 

 ary fauna," has been decidedly contradicted by Alexander Agassiz. 

 He claimed, on the ground of "exact experiments" carried on during 

 the Blal<e expedition, in 1878, that the greater part of the ocean con- 

 tains absolutely no organic life, and that the pelagic animals go down 

 no deeper than 100 fathoms. "The experiments finally show that 

 the surface fauna of the sea is actually limited to a relatively thin layer, 

 and that no intermediate zone of animal life, so to speak,' exists between 

 the fauna of the sea bottom and of the surface" (15, pp. 46, 48). 



