109 



Halymenia dilatata Zanard. 



Norn, Jap, ; Fii-iri-sttsa. 

 PL. CLXXVI; PL. CLXXVII, Fig. 3-4. 



Halymenia dilatata Zanard. Plant. Mar. Ruhr. enum. p. 280, t. V, f. 1. 

 J. Ag. Anal. Alg. 1892, p. 53.Sebdenia dilatata (Zanard.) De Toni Syll. 

 Alg. IV, p. 531 (partim). 



Fronds rising from a small scutate disc, with or without a short 

 thickish stem, abruptly expanding with reniform base into a broad mem- 

 brane which is mostly suborbicular or transversely expanded or sometimes 

 broadly oblong, undulato-curled, simple or more or less lobed, attaining as 

 much as 15-20 cm. in breadth and height. Margin entire, crenate or 

 roughly subdentato-sinuose or fimbriated with ligulate lobules and more 

 or less crisped, rarely proliferous from surfaces with small papillose or 

 ligulate processes. Surface not evenly flat but roughly undulato-bullated. 

 Tetraspores scattered all over the surfaces of frond. Cystocarps minute 

 dots, densely scattered all over the surface of frond. Colour purplish red, 

 often variegated with irregularly shaped small patches. Substance gela- 

 tinoso-membran aceous and the plant firmly adheres to paper in drying 

 except stem. 



Hab. : In deep places at 3-9 fath. Ryukyu, Kyushu, Kishyu. 



Structure of frond and cystocarp is that of Halymenia. Auxiliary 

 cell which is rather large, oval or oblong, is formed as a branch of cor- 

 tical filament and is situated at the point where some 5 or more cortical 

 filaments converge (PI. CLXXVII, fig. 3, a). Those filaments afterward 



PI. CLXXVI-CLXXX, June 1921. 



