256 CHARLES DARWIN 



other plant attains so great a length as three hundred and 

 sixty feet, as stated by Captain Cook. Captain Fitz Roy, 

 moreover, found it growing 7 up from the greater depth of 

 forty-five fathoms. The beds of this sea-weed, even when 

 of not great breadth, make excellent natural floating break- 

 waters. It is quite curious to see, in an exposed harbour, 

 how soon the waves from the open sea, as they travel through 

 the straggling stems, sink in height, and pass into smooth 

 water. 



The number of living creatures of all Orders, whose exist- 

 ence intimately depends on the kelp, is wonderful. A great 

 volume might be written, describing the inhabitants of one 

 of these beds of sea-weed. Almost all the leaves, excepting 

 those that float on the surface, are so thickly incrusted with 

 corallines as to be of a white colour. We find exquisitely 

 delicate structures, some inhabited by simple hydra-like 

 polypi, others by more organized kinds, and beautiful com- 

 pound Ascidiae. On the leaves, also, various patelliform shells, 

 Trochi, uncovered molluscs, and some bivalves are attached. 

 Innumerable Crustacea frequent every part of the plant. On 

 shaking the great entangled roots, a pile of small fish, shells, 

 cuttle-fish, crabs of all orders, sea-eggs, star-fish, beautiful 

 Holuthuriae, Planariae, and crawling nereidous animals of a 

 multitude of forms, all fall out together. Often as I recurred 

 to a branch of the kelp, I never failed to discover animals 

 of new and curious structures. In Chiloe, where the kelp 

 does not thrive very well, the numerous shells, corallines, and 

 Crustacea are absent; but there yet remain a few of the 

 Flustraceae, and some compound Ascidiae; the latter, how- 

 ever, are of different species from those in Tierra del Fuego : 

 we see here the fucus possessing a wider range than the ani- 

 mals which use it as an abode. I can only compare these 

 great aquatic forests of the southern hemisphere with the 

 terrestrial ones in the intertropical regions. Yet if in any 

 country a forest was destroyed, I do not believe nearly so 

 many species of animals would perish as would here, from 



7 Voyages of the Adventure and Beagle, vol. i. p, 363. It appears that 

 sea-weed grows extremely quick. Mr. Stephenson found (Wilson s Voyage 

 round Scotland, vol. ii. p. 228) that a rock uncovered only at spring-tides, 

 which had been chiselled smooth in November, on the following May, that is, 

 within six months afterwards, was thickly covered with Fucus digitatus two 

 feet, and F. esculentus six feet, in length. 



