THE SEA-SHORE. 183 



But we can scarcely conceive any circumstances 

 under which the sea-weed would be liable to be 

 only partially submersed. When the returning 

 tide rose so high as to wet one portion of a plant, 

 it would necessarily be high enough to cover the 

 whole ; and consequently, in the case of sea-weeds, 

 no provision is made for the transmission of fluids 

 through the whole extent of the plant, each part 

 only recovering its freshness as it becomes im- 

 mersed. One kind, approaching in habit some 

 species of lichen, and therefore called Lichina, 

 grows on rocks, which are only occasionally moist- 

 ened by the sea-water ; nevertheless, it suffers no 

 detriment from its prolonged and often-repeated 

 abstinence, but on the first sprinkling of a few 

 drops of spray immediately recovers its vigour. 



LICHINA PYGM2EA. LICHINA PYGM^EA. 



Natural size. Magnified. 



Very different from the above are a few species, 

 which are, during the greater part of their exist- 

 ence, attached to no solid substance, but float 

 about at or near the surface of the sea. The 

 most remarkable of them is the " Sargassum vul- 

 gare" the " Tropic Grape" of sailors. It is 

 worthy of attention, not only from its wandering 



