265 



THE GEOGRAPHICAL DISTRIBUTION, HABITAT, 

 AND MIGRATIONS OF FISHES. 



Continued from page 229. 



It would be certainly assuming too much, to assert 

 that, the truly pelagian fish excepted, no other spe- 

 cies cross the ocean without the guidance of those 

 aquatic plants known by the vulgar name of the gulf 

 weed and among which the Fucus natans, L. is 

 probably the most conspicuous ; but certain it is that 

 numerous gelatinous animals, small mollusca, scyllsea 

 and pelagic crabs, together with the fry of different 

 species of fish, harbour in this weed, wherever it is 

 taken up and examined. In steering towards the 

 Equator, it is usually first observed in fields and 

 islands on the surface of the sea, south of Madeira, 

 and if we take this place for a point of departure, the 

 trade winds convey it along with the current towards 

 the north point of South America, whence a part is 

 drawn into the Canibean Sea, and Gulf of Mexico ; 

 after sweeping round the shores, it escapes again by 

 the Straits of the Gulf of Florida, in a north-eastern 

 direction with the stream, till the north-westerly 

 winds and the arctic currents conjointly carry the 

 weed eastward towards the Azores, from whence, 

 tropical evaporation draws it again southward to 

 recommence the same gyration."^ There is a simi- 

 larly revolving current, south of the Equator, bearing 

 the game kinds of marine vegetation and their con-* 

 comitant inhabitants, but much more scattered, and 



*Doctor Leach, in M.S.S., enumerates several genera of Mala- 

 costraca, &c., which Mr. Cranch took from these plants. Some 

 of them are now published in the Transactions of the Plymouth 

 Society. I have myself found amon^ other species an Albula 

 (mullus) Plumieriand small Serrani off Trinidad entangled in this 

 weed. It was no doubt an immense field of fucus natans which 

 impeded tlie progress of the Carthaginians, on their expedition of 

 discovery along the West coast of Africa; and the same plant 

 also caused great uneasiness to the crews of Columbus's ships, 

 though it could not have been new to them as it is not unfre- 

 quently cast ashore on the coast of Spain. 



VOL. V. — 1835. KK 



