The cold night of the abyss. 



In this " biological extract of the log-book of F. N. R. S. 3 ", Professor Monod gives a 

 brief summary of phenomena that have eluded a hundred years of oceanographic research: 

 the firm nature of the bottom and the existence of deep-seated currents. Above all, he has 

 seen fishes alive that we only knew from the blind sampling of dredges and vertical nets. How 

 can we write about abyssal creatures when, before long, new observations will undoubtedly 

 destroy conceptions built up from results that have been patiently got by great scientific exped- 

 itions. 



For a long time the submarine world was believed to be profoundly silent. Modern micro- 

 phones have revealed that it is nothing of the sort. On the contrary, all those animals that 

 were thought to be dumb produce an absolute hubbub of noises. For a long time 

 one understood that the luminous organs of animals flashed with only a dim bluish or purplish 

 light in the darkness of the depths. But Th. Monod tells us of deep-sea, mid-water fireworks 

 casting a strong light into the abyssal blackness. However, this luminescence must be restricted. 

 Certain parts of the deep-sea floor must be quite dark, otherwise we would be unable to under- 

 stand the extreme development of tactile appendages in blind forms to compensate for a defic- 

 iency or lack of vision. Nevertheless, species with enormous eyes and those without eyes have 

 both been recorded from the same level and even from the same place. The rapid improve- 

 ments in modern equipment will undoubtedly enable us to resolve these many problems in 

 abyssal biology. 



Chimaeras (Chimaera monslrosa), the male (above) and the female. Two eggs are stuck in the ooze. 



The purple-blue coloured type of deep-sea fish living above the oozes of the continental 

 shelf is made up of species with very large eyes and a snout projecting into a fleshy or bony 

 rostrum. The first dorsal fin is protected by a strong spine or spiny rays and the rear part ot 

 the body tapers into a long filament. Such are the chimaeras, or Holocephali, the surviving 

 evidence of the first stocking of deep waters with cartilaginous fishes — and the macrourids 

 which have a bony skeleton and are related to the cod-like fishes. Close by these specialised 

 forms, swimming along the bottom, are argentines (Argentina silus), ancestral salmonids, and 

 telescope-fishes (Epigoniis telescopiiim), sea-perches that have taken to the depths and become 

 almost unrecognisable as such, because of the enormous development of their eyes. 



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