Notices of Memoirs — Antarctic Exploration. 273 



produced by evaporation and southward-flowing surface-currents, 

 and these deeper layers of relatively warm water appear likewise to 

 be slowly drawn southwards to the Antarctic area to supply the 

 place of the ice-cold currents of surface water drifted to the north. 

 This warm underlying water is evidently a potent factor in the 

 melting and destruction of the huge table-topped icebergs of the 

 southern hemisphere. While these views as to circulation appear to 

 be well established, still a fuller examination of these waters is most 

 desirable at different seasons of the year, with improved thermometers 

 and sounding machines. Indeed, all deep-sea apparatus has been 

 so much improved as a result of the ' Challenger ' explorations, that 

 the labour of taking specific gravity and all other oceanographical 

 observations has been very much lessened." 



In speaking of the pelagic life of the Antarctic Ocean, the author 

 mentioned that " In the surface waters of the Antarctic there is 

 a great abundance of diatoms and other marine algge. These 

 floating banks or meadows form primarily not only the food of 

 pelagic animals, but also the food of the abundant deep-sea life 

 which covers the floor of the ocean in these South Polar regions. 

 Pelagic animals, such as copepods, amphipods, molluscs, and other 

 marine organisms, are also very abundant, although species are 

 fewer than in tropical waters. Some of these animals seem to be 

 nearly, if not quite, identical with those found in high northern 

 latitudes, and they have not been met with in the intervening 

 tropical zones. The numerous species of shelled Pteropods, Fora- 

 minifera, Goccoliths, and Ehabdoliths, which exist in the tropical 

 surface waters, gradually disappear as we approach the Antarctic 

 circle, where the shelled Pteropods are represented by a small 

 Limacina, and the Foraminifera by only two species of Glohigerina, 

 which are apparently identical with those in the Arctic Ocean. 

 A peculiarity of the tow-net gatherings made by the ' Challenger ' 

 Expedition in high southern latitudes, is the great rarity or absence 

 of the pelagic larvae of benthonic organisms, and in this respect they 

 agree with similar collections from the cold waters of the Arctic 

 seas. The absence of these larvge from polar waters may be 

 accounted for by the mode of development of benthonic organisms 

 to be referred to presently. It must be remembered that many of 

 these pelagic organisms pass most of their lives in water of 

 a temperature below 32° F., and it would be most interesting to 

 learn more about their reproduction and general life-history." 



As to the benthos life of the Antarctic Ocean, Dr. Murray said : — 

 " At present we have no information as to the shallow- water fauna 

 of the Antarctic continent ; but, judging from what we do know of 

 the off-lying Antarctic islands, there are I'elatively few species in 

 the shallow waters in depths less than 25 fathoms. On the other 

 hand, life in the deeper waters appears to be exceptionally abundant. 

 The total number of species of Metazoa collected by the 'Challenger' 

 at Kerguelen in depths less than oU fathoms was about 130, and the 

 number of additional species known from other sources from the 

 shallow waters of the same island is 112, making altogether 242 



DECADE IT. VOL. T. NO. YI. 18 



