184 



THE OPAL SEA 



Red algce. 



cold waters bordering upon the arctic regions, 

 though some of them are found in the tropics. 



Further out in the ocean and deeper down 

 than any others, clinging to rocks, banks, shells, 

 wrecks, even other plants, are the red algce be- 

 longing to the class Rhodophycece or Floridece. 

 These are the most beautiful of all, not only in 

 the brilliancy of their coloring, but in the deli- 

 cacy of their forms and patterns. The majority 

 of them are crimson, rose, or some other shade 

 of red (though sometimes showing purple, yel- 

 low or violet), owing to the presence of phy- 

 coerythrin, a pigment that outbulks the chloro- 

 phyll and gives the reddish tinge. The forms 

 are not large. Some have leaf-like branches 

 and bear a protuberant fruit as tasteless as the 

 apples of the Dead Sea shore; others are saw- 

 edged, rod-like, feathery, threaded, membran- 

 ous, cartilaginous. All the corallines with bases 

 stone-coated with lime, all the dulses with their 

 blood-red colorings, all the gelatinous sea- 

 mosses from which are made Irish moss, agar- 

 agar, and Japanese isinglass, belong here. 



In addition to these large divisions there are 

 many plants ungrouped and unclassified; and 

 standing beside them along the hills and val- 

 leys of the ocean world are organisms that 

 look vegetable and yet are animal. Time 



Dulses and 

 sea mosses. 



