362 NATURAL SCIENCE [December 



out in the abysses, entirely upsetting our present ideas of the geo- 

 logical nature of the sea-bottom. Besides, we have no other means 

 for accounting for the distribution of the terrestrial fauna, more 

 especially in the southern hemisphere, except by assuming that 

 great changes have taken place in the extent and position of conti- 

 nental land, and, moreover, that these changes were still in progress 

 at periods at which our present fauna, or at least part of it, was 

 already in existence." 



The question of the existence of a " mid-water fauna " is con- 

 sidered by.Dr Giinther to be still an open one, to be " decided only 

 by continued tow-net experiments in great depths of the open ocean, 

 with a bottom of clean ooze or mud." Agassiz, as is well known, 

 maintains that there is no such fauna. Dr Giinther, however, 

 observes that the experiments of the distinguished American 

 naturalist " prove too much. His tow-nets came up always empty 

 from the intermediate zones. It is very singular that he should 

 not have caught even some of the dead bodies which, like rain, 

 drop constantly from the surface to the bottom. Further, so far as 

 fishes are concerned, there is no reason why certain forms should 

 not permanently inhabit intermediate zones, inasmuch as also pelagic 

 fishes are undoubtedly free swimmers for nearly the whole of their 

 life, without being tied to the proximity of terra firma. The ova of 

 many species which live in the mature stage at the bottom of great 

 depths are pelagic, and hatched at or near the surface. The young 

 continue to live for some time under pelagic conditions {Plagusiae, 

 Lcptocephali, Polyprion), but as they grow they descend to the deep 

 sea. It is very improbable that this descent is rapid ; it must be 

 gradual in order to allow the physiological functions to get used to 

 abyssal conditions ; or, in other words, these fish must live for some 

 time in mid-water." 



Finally, Dr Giinther adds an appropriate plea for more deep-sea 

 work in the Indian Ocean and the Antarctic regions. The ordinary 

 survey of the sea's round British India is now nearly completed, but 

 researches on the fauna have only proceeded just far enough to 

 demonstrate their interest and biological importance. " It seems a 

 pity," as Dr Giinther remarks, " that while the experience gained on 

 board the ' Investigator ' is at least still partly available in the ser- 

 vice, no further benefit should accrue from it for science." In refer- 

 ence to the Antarctic Ocean, he points out that our knowledge of 

 its abyssal life rests merely on six trawlings of the ' Challenger.' We 

 trust that ere long the British Government will be induced to help 

 further in this important biological work. To use Dr Giinther's 

 words, " the beneficial influence which every purely scientific under- 

 taking exercises upon mankind reaches far beyond its immediate 

 aim." Science " is the mother as well as the daughter of peace." 



