1 8 PROCEEDINGS OE THE 



have been dredged in over 1000 fathoms. Tet plants per- 

 form an important part in the economy of the Deep Sea : they 

 flourish in incredible numbers near the surface, but, after death, 

 find their way to the bottom ; the ooze or mud is full of their 

 remains and of the dead bodies of pelagic Foraminifera, retaining 

 much nutritive substance, and offering a rich pasture-ground for 

 numberless Invertebrates which, in their turn, serve as food for 

 the carnivorous animals of the Deep Sea. A large proportion of 

 these plants are known, not from specimens collected near the 

 surface wliere they live, but from deposits withdrawn by the 

 sounding-lead or dredge from depths of, may be, 3000 fathoms 

 or more*. 



Chronological accounts of Deep-sea work have been given 

 by several of the leaders in oceanic research, such as Wyville 

 Thomson, Alexander Agassiz, and especially John Murray. The 

 latter has given us in his " Summary " of the ' Challenger ' 

 results not only the most perfect guide to the work of the 

 Expedition and the 50 volumes of the Eeports, but an invaluable 

 contribution to the Biology of the Oceans. His enquiry into the 

 bathymetrical and horizontal distribution of the marine fauna, 

 and into the genetic relations of the fauna of the so-called 

 " mud-line " to Deep-sea animals without a free-swimming larval 

 stage of development, as well as to shallow-water forms with 

 pelngic larvae, has opened a new era of investigation to succeeding 

 workers on the same field. 



Thinking that some points of interest might be brought out 



more prominently by arranging the Deep-sea work geographically, 



than by using a chronological order, I propose to treat of it 



to-day under geographical headings. But I do not wish you to 



suppose for a moment that these geograpliieal areas or divisions are 



intended to represent distinct faunistic regions. My own opinion 



is the same which I have held for many years, viz. that, as regards 



horizontal distribution, the Deep-sea fauna is one indivisible 



whole; and that such types as, in the present state of our 



knowledge, seem to be characteristic of some particular division 



of the ocean, are either foreign to — that is, accidentally or 



ignorantly imported into — the Deep-sea fauna, or forms, the 



wide range of which has not yet been ascertained. In some 



cases other considerations besides geographical have led me to 



delimitate those areas in a way most convenient for my purpose. 



If any important question has been tried or settled within a 



particular area, I propose to refer to it under that heading. 



Pinally, I have only to ask for your patient indulgence, when 

 you bear me recounting facts with which some, or even the 

 majority, of those present may be well acquainted, 



' * See ' Challenger' Summary, lists, and Agassiz, Bull. Mus. Comp. Zool. xiv. 

 p. 313. 



