.ir 



392 



GEOGEAPHICAL DISTEIBUTION AKD 



[Ch. XL. 



to tlie British seas. He lias siiggestecl tliat cold cnrrents 

 wliich. prevail from Cape Horn to the equator^ and are there 

 met by other cold waters, may by their direct influence, as 

 well as by their temperature, facilitate the passage of ant- 

 arctic species to the Arctic Ocean. 



Remarkable accnmnlations of that species of sea-weed 

 generally known as gulf-weed^ or sargassum, occur north of 

 the equator in the Northern Atlantic. Columbus and other 

 navigators, who first encountered these banks of algse, com- 

 pared them to vast inundated meadows, and stated that they 

 retarded the progress of their vessels. This mass of floating 

 vegetation, exceeding the British Isles in area, lies between 

 latitudes 20° and SS'' to the south-west of Europe. 



Sir Hans Sloane stated in 1696 that this weed grows on the 

 rocks about Jamaica, and is know^n to be *^ carried by the 

 winds and current towards the coast of Florida and thence 

 into the North-American ocean, where it lies very thick on 



the surface of the sea.'"^ 



Humboldt first suggested that it occunies an eddv in that 



part of the Atlantic where the Gulf 



om the north ; and Maury 



stream is met by the 

 ives a similar explana- 



tion of another large bank of kelp and drift-weed in the 

 North Pacific, to the northward of the Sandwich Islands, 

 and of another in the Southern Ocean around Kerg'uelen's 



Land between lat. 40 



t 



The late Robert Brown inclined to the opinion that the 



mi 



coasts of the Gulf of Florida. When floating on the ocean 

 it propagates itself rapidly by new fronds which are contm- 

 ually pushed out from the old ones ; and the larger portion of 

 it being produced 



circumstances 



may perhaps become so modified as not to be easily 

 identifiable with the original stock from which it is derived.J 

 The late Edward Forbes conceived that this weed first grew 

 on an old coast-line since submero^ed : this coast having 



* Phil. Trans. 1696. 



t See map of Sargassum seas, taken 



J E. Brown, Mode of Propagation of 

 Gulf-M^eed, Miscell. Works, vol. i. Bay 



from Maury by Andrew Murray, Geog. Society, 1866. 

 Dist. of Mammals, 186G. 



