626 



DEPTHS OF THE OCEAN 



forms in question seems explicable when compared with the 

 distribution of temperature. In Chapter VH. we noted that 

 the temperature along the ocean -floor is very uniform, and 

 consequently the abyssal bottom-fish, like Macriirus armatus 

 and M. filicauda, have a very wide distribution. Throughout 

 the abyssal region of the Pacific, Atlantic, and Indian Oceans 

 the temperature varies only between i' and 3° C, and only 

 far south in the Antarctic do we meet with temperatures below 

 0° C. The water-layer from 5000 or 6000 metres up to 1500 



vious catches cf 

 C. microdon 

 ■\- Previous catches of 

 C. signata 



10 L.Wot G. L E of G. 10 



OCyclothone Signata and microdon 

 caught bv "Michael Sars" 



Fig. 476. 



metres is practically homogeneous as to temperature, and if it 

 were possible for a fish to swim so far, keeping constantly at 

 a depth of 1500 metres, it might travel from India to Australia, 

 then westwards past the Cape, and northwards through the 

 Atlantic as near to Iceland as the depth would permit, 

 encountering all the way no greater variations in temperature 

 than from 3 to 5° C. Even at a depth of 1000 metres con- 

 ditions are very uniform, for only in the Indian and North 

 Atlantic Oceans do the temperatures rise to 7° or 8^ C, 



