398 THE INHABITANTS OF THE SEA. 
the savannas of America, nor on the heaths or in the pine forests 
of Northern Europe, is such a uniformity of vegetation found as 
in those boundless maritime meadows. 
** The masses of sea-weeds,” says Meyen, “ covering so vast an 
extent of ocean have ever since the time of Columbus been the 
object of astonishment and inquiry. Some navigators believe. 
that they are driven together by the Gulf Stream, and that the 
same species of Sargassum plentifully occurs in the Mexican Sea ; 
this is however perfectly erroneous. 
“ Humboldt was of opinion that this marine plant originally 
grows on submarine banks, from which it is torn by various 
forces; I for my part have examined many thousands of. speci- 
mens, and venture to affirm that they never have been attached 
to any solid body. Freely floating in the water, they have 
developed their young germs, and sent forth on all sides roots 
and leaves, both of the same nature.” 
Thus the Sargassum seems to be the indigenous production of 
the sea where it appears, and to have floated there from time 
immemorial. Its swimming islands afford an abode and 
nourishment to a prodigious amount of animal life. They are 
generally covered with elegant sertularias, coloured vorticellas, 
and other strange forms of mariné existence. Various naked or 
nudibranchiate mollusks and annelides attach themselves to the 
fronds, and afford nourishment to hosts of fishes and crustaceans, 
the beasts of prey of this little world. 
Similar aggregations of sea-weeds are also met with in the 
Indian and Pacific Oceans, in the comparatively tranquil spaces 
encircled by rotatory currents. Their rare occurrence on the 
surface of the sea may serve as a proof of the restless motion of 
its waters. Were the ocean not everywhere intersected by cur- 
rents, it would most likely be covered with sea-weeds, opposing 
serious, if not invincible obstacles to navigation. 
The Red sea-weeds, Rhodosperms or Floridex, are by far the 
most numerous in species, and undoubtedly the most beautiful and 
perfect of all the alg. They love neither light nor motion, and 
generally seek the shade of larger plants on the perpendicular sides 
of deep tide-pools removed from the influences of the tides and 
gales. They mostly grow close to low-water mark, and are to be 
seen only for an hour or two at the spring-tides, during which, as 
is well known, the deepest ebbs take place. To this group be- 
