RED ALG^. 265 



It may be looked for along the coast, from New 

 York to Massachusetts Bay, though I have collected 

 it only at Wood's Holl and New York Bay. I have 

 specimens from Narragansett Pier. It is not a very 

 common plant, though Harvey says it may be found 

 in several places in New York Harbor, from Hell 

 Gate to Fort Hamilton. 



Callithamnion versicolor, Ag. 



This beautiful little Callithamnion, represented in 

 Fig. I, Plate XVIII., has all the delicate and cobweb 

 fineness of filament which characterizes the last 

 species. But it may be easily distinguished from 

 that and every other species of Callithamnion , by 

 the peculiarity which its name indicates, viz. : its 

 striking and beautiful diversity of color. Some parts 

 of the frond will be a brilliant rosy red, while others 

 are an equally brilliant, full green. Sometimes a 

 branch will begin a red and end a green, or a 

 brown, or a yellow. Again, some one of the second- 

 ary branches on a primary will be all red, and an- 

 other just by the side of it, will be a green or a 

 yellow, and so on. Sometimes fully half a dozen 

 different colors or shades will appear in the same 

 frond, and I have them where the whole plant is as 

 brilliant a green as an Ulva or an Enter otnorpha. 



