THE PELAGIC FAUNA AND FLOKA. 211 



of yellowish green or golden olive, reaching over the dark blue 

 water of the Atlantic. 



The " Challenger " sailed round this so-called Sargasso Sea, 

 but nowhere encountered it m sufficient quantities to become 

 an impediment to navigation. We meet with this gulf -weed 

 everywhere in the Gulf of Mexico, but scattered and only in 

 small patches, and to the leeward of the Windward Islands. 

 It is very abundant in the old Bahama Channel, and mod- 

 erately common all along the course of the Gulf Stream from 

 off Charleston to Cape Hatteras. The largest mass of gulf- 

 weed I have encountered was in making the passage from 

 St. Thomas to Havana.^ While steaming' within sioht of the 

 northern shores of Porto Rico and of San Domingo, we were 

 never out of sight of immense accumulations of gulf-weed, parts 

 of which rose a few inches above the water, the whole forming 

 long trains which trailed with the winds and currents. The 

 weed became less and less common as we approached the old 

 Bahama Channel. But these masses of Sargassum were of 

 slight thickness, and were mere floating patches, more or less 

 entangled. 



The numerous young and tender leaves found on every stem 

 show that the weed is in a most flourishing condition, and is 

 not merely dead w^eed floating" about in the great vortex of oce- 

 anic circulation. It is not known what becomes of the gulf- 

 weed annually driven by the equatorial current through the 

 passages of the West India Islands into the Caribbean. The 

 bidk of the weed which passes through the Windward Passage 

 probably finds its way through the Yucatan Channel and the 

 Straits of Florida into the Gulf Stream proper, but its final fate 

 is not known. The amount of oulf-weed met with north of. 

 Cape Hatteras in the track of the Gulf Stream is small ; it grad- 

 ually increases as one goes south. 



One of the objects of the " Talisman " expedition was to 

 investigate the Sargasso Sea. The French explorers " nowhere 

 met the enormous masses of floating Sargassum, which the old 

 navigators compared to floating prairies." While sailing, the 



^ Commander Bartlett found large masses of gulf-weed on the southern edge of 

 the Gulf Stream. 



