1880. 1 Mr. 11. N. Mosclc}/ on Life in the Deep Sea. 331 



WEEKLY EVENING MEETING, 



Friday, March 5, 1880. 



Gkorgk Busk, Esq. F.R.S. Treasurer and Vico-rrcsidciit, 

 iu tbc Chair. 



IT. N. MosELEY, Esq. MA. F.R.S. 



Deep-Sea Dredging and Life in the Deep Sea. 



(This lecture has been published in full in ' Nature.') 



After some account of the physical conditions under which life 

 occurs in the deep sea, the lecturer described the improved apparatus 

 for deep-sea dredging, which has been introduced since the 'Challenger' 

 Expedition by Mr. Alexander Agassiz. A steel wire rope with a 

 hemp core only l^^y inch in circumference is used. Three or four 

 hauls can be made with it in a day in deptlis in which only ono 

 would be made by the ' Challenger.' A reversible trawl is used iu tho 

 place of the old net, which was useless if it fell on its back on the 

 bottom. 



All animal and plant life originated in tho sea in shallow water, 

 and spread thence on to the land and into tho depths. Only ono 

 plant exists in the depths, a parasitic fungus which infests corals. 

 The absence of sunlight excludes others. Many genera of all groups 

 of animals and even not a few species range from the shores down to 

 very great depths. Ono species of coral ranges from 30 to 2900 

 fathoms. There are, however, certain well-marked deep-sea forms 

 which arc not now met with iu shallow water, unless in Polar 

 regions. 



There being scarcely any difference in the physical conditions of 

 life from a depth of 500 fathoms downwards, the deep-sea fauna 

 exhibits no zones of distribution in depth. Its upper limit varies 

 much in position, approaching shallow water in the higher latitudes, 

 but even in some i)laccs in the tropics coming within 300 or possibly 

 100 fathoms of the surfiice. It is impossible to recognize a geo- 

 logical deposit as having been formed in the deep sea, from the 

 nature of its fossil contents. 



The deep-sea fauna is world-wide in its distribution, there being 



