12 Prof. T. Fuclis on the Deep-sea Fauna. 



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region". Travellers in the tropics represent in lively colours 

 the overpowering impression produced upon the spectator by 

 a living coral-reef with its multifarious and varied fauna. 

 But what an impression would such a reef produce if its inhabi- 

 tants shone at night in the most different colours ! But 

 no traveller has described any such phenomenon. The lit- 

 toral coral-reefs are perfectly dark at night ; but if deep-sea 

 corals are brought to the surface, nearly all of them are seen 

 to glow with the most vivid colours. 



Various naturalists have already noticed, and the fact has 

 lately been again brought prominently forward by Moseley, 

 that the pelagic fauna shows a very great resemblance to the 

 deep-sea fauna ; for example, the Seopelidas and Sternopty- 

 chicke are among the most strikingly pelagic animals, but at 

 the same time among the most characteristic of deep-sea 

 animals. It is well known that by far the greater part of the 

 pelagic animals are animals of darkness, dwelling during the 

 day in the obscure depths of the sea, and only coining to the 

 surface at night. But if it be the case that the deep-sea 

 animals are in their nature animals of darkness, the numerous 

 relations manifested between the deep-sea fauna and the pelagic 

 fauna can no longer surprise us in the least ; for the pelagic 

 animals are then in their nature- fundamentally nothing but 

 deep-sea animals. In connexion with this it must further be 

 indicated that luminosity is just as much diffused among the 

 pelagic animals as among those of the deep sea, and that the 

 above-mejitioned pelagic Scopelidse and Sternoptychidae espe- 

 cially are as well provided with luminous organs as their 

 relatives in the depths. 



By the conception of the deep-sea fauna as a fauna o( 

 darkness, moreover, it may be quite easily explained why it 

 appears to be so completely independent of temperature in its 

 occurrence, and at the same time why it commences nearly at 

 the same depth over the whole surface of the earth. 



There is, however, a means by which we may test the' 

 correctness of the view here put forward in a very simple and 

 exact manner. Thus, if it be true that the animals of the 

 deep sea are nothing but animals of darkness, animals must 

 occur in the caverns and grottoes of the sea which show a 

 certain resemblance to deep-sea animals, or even directly agree 

 with them. No direct investigations in this direction are 

 known to me ; but nevertheless there is a series of facts which 

 seem to show that such conditions actually exist. Thus, for 

 example, in the great depths of the Lake of Geneva there is a 

 blind Amphipod, Nipfutrgus styghis\ but precisely the same 

 animal occurs in springs as well as in the caverns of Carniolia, 



