422 Scientific Intelligence. 



prove the existence of an intermediate deep-sea fauna in the depths 

 between the surface fauna and the deep-sea fauna. 



From the depth of 1300 meters Dr.' Chun brought up a large 

 pelagic fauna. Small Craspedote Medusae, Ctenophores, Dyphise, 

 Tomopteridse, Sagittse, Alciopidse and numberless Copepods, 

 Stylocheirse, larvae of Decapods, Appendicularise, Pteropods and 

 small transparent Cephalopods. Dr. Chun assumes that where he 

 found this mass of Invertebrates there were no currents and that 

 so rich a booty brought up by a hap-hazard cast of the net indi- 

 cates a wonderful richness of the deep-sea pelagic fauna, espe- 

 cially when we remember that surface pelagic fishing is only suc- 

 cessful in the wake of tide currents, calm streaks and the like. 

 But there is nothing to show that so close in shore there is not a 

 more or less active interchange of the fauna from the shore slopes 

 to that of the greater depths. Should the observations of Dr. 

 Chun be repeated off shore in the deep water of oceanic basins 

 and the existence of this deep-sea pelagic fauna proved beyond 

 a doubt, it will help to explain the manner in which the deep- 

 sea fauna obtains its food ; nor will it be necessary to suppose, 

 as he seems inclined to do, that these deep-sea animals are 

 wholly dependent on the broth concocted at the surface and 

 passing down in a ceaseless rain upon the bottom. Surely 

 no one who has trawled and dredged in the deep sea can have 

 failed to note the large number of free-swimming animals 

 such as Crustacea, Cephalopods, Annelids and fishes of which 

 only an. occasional specimen could be caught by the slow moving 

 dredge or trawl, while a faster trawl brought up the more nimble 

 deep-sea types. It seems to us that the results of Chun merely 

 prove that in a close sea, near shore, even at considerable depth 

 there is a great mixture of true deep-sea types and surface pelagic 

 animals which sink at certain times far beyond the limits usually 

 assigned to them. Certainly no one who has engaged in deep-sea 

 work has ever supposed that there were not at the bottom or near 

 the bottom free-swimming animals which occasionally found their 

 way to the surface while many of the so-called surface pelagic 

 types have been proved by deep-sea expeditions to be the young 

 of abyssal species. Chun has however clearly proved that many 

 embryonic stages of surface pelagic animals are only found at 

 considerable depths. Deep-sea fishing with a properly closing 

 net promises to be a material help to embryological investigations. 

 Chun looks upon the slight changes of temperature as the impor- 

 tant factors in determining the periodic rising and sinking of the 

 surface pelagic fauna. He thinks the great increase of tempera- 

 ture at the surface compels surface pelagic animals to seek cooler 

 depths. While this is undoubtedly true for some groups it does 

 not hold good for the larger number and we are more inclined to 

 consider the condition of the surface, whether calm or rtiffled by 

 waves and winds, as a more powerful influence. Thus while there 

 is always a richer pelagic fauna to be collected at night it 

 is only on calm nights that a good harvest will be obtained. Yet 



