WEST INDIAN MAEINE FAUNA. 



347 



interminable distances with the ebb and flow, and in certain places, such as the 

 trough north of Puerto Rico, it covers spaces vast enough to merit the name of 

 "marine prairies." This plant is not entirely of pelagic origin, for it grows 

 also on the rocks of the Antilles and Bahamas and on the reefs of Florida. 

 But botanists who have explored the Sargasso Sea have been unable to determine 

 the process of reproduction, which seems to be effected by the continuous growth 

 of fresh shoots or sprouts, which become detached from the parent stem by the 

 action of the waves. 



Till recently it was supposed that the marine fauna was confined to the 

 surface or shallow waters, and that the stillness of death reigned in the gloomy 



Fig. 163. — Deposits on the Bed of the Atlantic and West India Watees. 



Scale 1 : 45,000,000. 



Mm 



Globigerine 

 mud. 



90" 



West or Green wic It 70' 



Eed clay. 



E3 



Corals, 

 Coralline mud. 



EH 



Silioious 

 sinds. 



Earthy deposits, 

 tellurian mud. 



Pteropod 

 mud. 



620 Miles. 



recesses of the deep. But the dredgings of the Blake and of other exploring 

 vessels in depths of over 2,000 fathoms have already increased the number of 

 crustacean forms from 20 to 150 species grouped under 40 new genera. The 

 deep waters of Florida, studied by Pourtales, are also found to be extremel}^ rich 

 in forms resembling the fossils of former geological epochs, and comprising 

 numerous phosphorescent species. In certain places the marine bed is covered 

 with living organisms, and in the channels of the Lesser Antilles, near Guadeloupe, 

 and the Saintes, about St. Vincent and Barbadoes, dense forests of pentacrini 

 undulate on the bottom like aquatic plants on stagnant waters. 



The geological character of these marine beds and of the surrounding shores is 

 far more varied than in the Atlantic Ocean. The muddy deposits in the central 



