PELAGIC ANIMAL LIFE 627 



neglecting the somewhat higher temperatures found off the 

 entrances to the Red Sea and the Mediterranean, but the 

 temperatures at 1000 metres usually vary only from 4° to 6° C. 

 The habitat of CyclotJione viicrodon is below 1000 metres, the 

 temperatures generally varying between 3' and 6' C, and the 

 wide range of this species must evidently be directly connected 

 with the wide areas occupied by these temperatures. On the 

 other hand, the area of distribution of C. signata at about 500 

 metres shows great differences in temperature in different 

 parts of the ocean. In the Indian and Atlantic Oceans, where 

 C. signata is found, temperatures at this depth are generally 

 above 10° C, sometimes even above 15° C. In the sea 

 between Newfoundland and Iceland, as well as south of lat. 

 40^ S., temperatures are below 5° C, and in these localities 

 C. siznata is absent. 



These facts, especially the conditions touching the wide 

 distribution of the bathypelagic C. niicrodon, assume more 

 general importance considering that we found many bathy- 

 pelagic species in the North Atlantic, which have been taken in the 

 deep water of other oceans. As instances of such forms I may Bathypelagic 

 mention the widely distributed medusae Atolla and Periphylla, ^°™^- 

 which were taken by us in the Northern Atlantic at nearly all 

 the localities and depths where C. microdon and C. signata were 

 taken. The genus Gigaiitocypris , taken at three stations in 

 our southern and at six stations in our northern section, 

 had previously been captured by the " Valdivia " in the Indian 

 Ocean. Three species of squids, taken by us in deep hauls 

 in the North Atlantic, were caught by the "Valdivia" in the 

 Indian Ocean, viz. Callitcnthis revcrsa, Mastigoteuthis flamniea, 

 Toxeuma belone. Bathypelagic fishes common to both these 

 oceans are : Malacosteus indicus, Cyema atrum, Mclamphaes 

 inizolepis, Cetomintus storeri, Melanocetus krec/ii, Ceratias cotiesi, 

 besides Aceratias macrorhinus indicus. These squids and 

 fishes are, however, represented by very few specimens, in 

 some cases only one from each ocean. The fact that we 

 caught several new species of the family Ceratiidse, as well 

 as such interesting forms as Gastrostomns bairdii and Gonostoma 

 grande, proves that a great field of research is still open to 

 systematic zoologists. The chart (Fig. 477) shows the dis- 

 tribution of Gonosto77ia grande. 



All the forms mentioned live, as far as we know, always in 

 deep water, except perhaps the early stages, which in some 

 cases occur closer to the surface, but certain cold-water 



