192 THE MARINE BOTANIST. 



Gymnogonc/rus, Frond filiform, dichotomons, 

 horny. Tetraspores strung together, contained 

 in wart-like sorL 



Polyides, Root scutate. Frond cylindrical, car- 

 tilaginous, forked. Favellse in spongy external 

 warts. Tetraspores scattered through the outer 

 stratum of the frond. 



Furcellaria, Root branching. Frond cylindrical, 

 dichotomous, cartilaginous. Favellse unknown. 

 Tetraspores contained in the swollen pod-like 

 upper branches of the frond. 



Dumontia. Frond cylindrical, tubular, membra- 

 naceous, of a dull red colour. 



Halymenia, Frond either compressed or flat, of a 

 gelatinous membranaceous structure, and pinky- 

 red colour. 



Ginannia. Frond cylindrical, dichotomous, tra- 

 versed by a fibrous axis. 



Kallymenia, Frond expanded, leaf-like, fleshy- 

 membranous, solid, of dense structure. 



Irid/sa, Frond expanded, leaf-like, thick, leathery 

 and fleshy. 



