60 MARINE 



ramified. The frond consists of a prostrate stem, from the lower 

 side of which root-like fibers or holdfasts descend into the hard 

 sand or coral, and from the upper side leaf- and branch-like 

 secondary fronds arise. These plants grow luxuriantly in tropi- 

 cal waters, extending over large surfaces, and are the chief food 

 of turtles. (Plate VIII.) 



C.prolifera. Frond or lamina flat and leaf-like, two to four inches 

 long, one half to three quarters of an inch wide, either simple or once 

 forked ; margin entire. Similar laminae spring from the surface or from 

 the edge or base of the different leaf -like portions. Laminae rise from 

 the upper side of the creeping, rooting stem. Its substance is somewhat 

 horny and translucent. 



C. Memicana. Prostrate, creeping stem, with rootlets or holdfasts 

 below, and leaf -like fronds above ; fronds simple or with one or two 

 branches deeply cut in narrow lobes nearly to the center. The species 

 abounds at Key West. (Plate VIII.) 



