SEA-WEEDS. 



157 



and so also are several other species. One of 

 them, the dark Polysiphonia, sometimes covers 



rocks by the sea-shore with dense patches, and 

 varies in height from a few inches even to two or 

 three feet. 



A very common production of our shores, the 

 strong-jointed Coralline (Corallina officinalis], is 

 now placed, with the other species of the genus, 



