MA BINE BOTANY. 



119 



Oceans at proportionally quiet spots, which are surrounded 

 by rotatory currents. That their appearance is such a 

 rarity may serve as a proof of the restless motion of the 

 waters. If this eternal circulation did not take place, 

 probably the sea would everywhere be covered with 

 weeds, which would be alone sufficient to impede navi- 

 gation. 



The Red Sea weeds, the Rhodosperms or Floridese, with 

 a short account of which we shall conclude this chapter, 

 embrace the greatest number of species, and, though not 

 the largest, are the handsomest in form and colour. They 

 like neither light nor motion, and hence remain beneath the 

 shadow and protection of the larger varieties, on the shelving 



POLYSIPHONIA PARASITICA. 



sides of deep hollows. Many of them grow at a depth below 

 the tidal influence, but the majority are found on the line of 

 low- water mark, and are only visible for a few hours during 

 the spring tides, when the sea runs out to the fullest extent. 

 To this group belong the wondrously- delicate Polysiphoniee, 

 Calithamnia}, Delessertise, Plocamiee, etc., which delight the 

 collector's heart by their gracefulness, and bright pink, 

 scarlet, or purple colouring, as well as the calcareous Coral- 

 lines and Nullipores, in which the external colouring is 

 absent, and which were long considered animal formations, 



