1894- TEMPERATURE AND MARINE ANIMALS. 283 



from 2,000 m. died when they came to the surface, while Mediterranean 

 animals from 2,000 m. survived. 



The Atlantic forms came from 0° to 20°, while those of the Medi- 

 terranean came from 13*^ to 20°. Hence it is obvious that temperature 

 is here the most important factor. 



In so far as real pelagic life is concerned, I therefore think that 

 the existence of an intermediate fauna is not to be regarded as proved, 

 neither in theory nor fact, and I would like to repeat Wyville 

 Thomson's old sentence : — " The fauna of the deep water is confined 

 to two belts, one near the surface, the other at the ground." 



According to my opinion, the abyssal fauna is chiefly a Benthos 

 fauna, more or less in connection with the bottom ; a kind of littoral 

 Plankton may be associated with it, but the true pelagic fauna does not 

 exceed a certain depth. 



I do not deny there is an intermediate zone of life, but it might be 

 supposed to consist, scanty as it is, principally of Nekton, that is to say, 

 of swimming animals, to which vertical distances are of no importance, 

 and which are not sensitive to the changes of temperature. All of 

 these are eurythermal, while, in contrast to them, most of the animals 

 of the Benthos and Plankton are stenothermal. 



In conclusion, after so much theory, I would merely repeat the 



fact that no case illustrates the great influence of temperature on the 



distribution of marine animals better than the well-known example 



of the Corals for the Benthos animals and the new one of Geryonid 



Medusae for the Plankton. 



Otto Maas. 



