Prof, T. Fuchs on the Deep-sea Fauna. 3 



and Pacific oceans is for by far the greater part connected with 

 the coral-reefs. If we imagine the coral-reefs with their 

 characteristic population to have disappeared, the Indian and 

 Pacific oceans would at one blow lose the whole splendour of 

 their animal life, and we should, instead of it, have before us 

 a comparatively poor and insignificant fauna, 



A third important element of the littoral fauna consists of 

 the beds of large bivalves, such as oysters, pearl-oysters, 

 scallop-shells, &c. These shell-beds appear generally to find 

 the maximum of their development in from 8 to 10 fathoms, 

 and no longer to occur below 20 fathoms. These shell-beds, 

 however, also attract many other animals, especially Ascidians, 

 worms,- and starfishes, which likewise form a definite associa- 

 tion of animals, and in part are specially attached to this 



dwelling-place. 



The seaweed-forests, coral-reefs, and shell-beds with their 

 inhabitants constitute the three most important animal-assem- 

 blages of the littoral region ; and we may say, without exag- 

 geration, that fully two thirds of the whole of the littoral 

 marine animals are more or less intimately connected with 

 one or other of these three assemblages. But as the seaweed- 

 forests as well as the coral-reefs and shell-beds are confined 

 to a depth of less than 30 fathoms, it follows directly that the 

 great majority of the littoral animals cannot descend much 

 below 30 fathoms in the sea. 



A second point that we have to bear in mind is the fact 

 that over the whole earth, at a depth of from 90 to 100 fathoms, 

 almost all the important types of the deep-sea fauna are 

 already represented, and the fauna already bears quite indu- 

 bitably the character of the deep-sea fauna. 



The celebrated Pourtales Plateau on the coast of Florida, 

 so exceedingly rich in deep-sea animals, begins at a depth of 

 90 fathoms, from which it descends gradually to 300 fathoms, 

 but without essentially changing its fauna in this further 

 course ; and the grounds near the island of Barbadoes, which 

 are so rich in deep-sea animals, are also situated at a depth of 

 from 80 to 100 fathoms. But at both these points we not only 

 find an astonishing abundance of deep-sea corals (over sixty 

 species have already been described), but there are already in 

 great plenty and variety true vitreous sponges (Hexactineilidse), 

 besides deep-sea Crustacea, Arctic Asterida, Echinothurice , 

 Pourtalesice, and no fewer than four pedunculate Crinoids 

 (Holopus, two Pentacrrm, and Rhizocrtnus*). 



* Of Mollusca there are near Barbadoes at this depth: — Caduhis sauri- 

 dent\ Dentalium disparUe\ Margarita asperrima ; Calliostoma Bairdii: Mi- 



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