192 CRyPTONEMIACE.E. v. 



are borne. The colour of the stem and branches is dark red ; of the ramuli a 

 brilliant lake. Substance of the ramuli succulent and tender. 



This very beautiful plant is a native also of the Mediterranean Sea and of the 

 shores of Brazil. It strikingly resembles Lomentaria avails in ramification, but has 

 a different structure and fructification. 



Plate XX. B. Fig. 1. Chrysymenia uvaria ; the natural size. Fig. 2, a ramulus 

 with coiiceptacles ; Jig. 3, section of a conceptacle ; both magnified. 



XVII. HALYMENIA. Ag. 



Frond cylindrical, compressed or flat, gelatinoso-membranaceous or fleshy, dicho- 

 tomous or pinnated, consisting of a thin, double membrane, separated by a few 

 internal, laxly set, articulated, branching filaments ; membrane composed internally 

 of roundish-angular, empty cells, externally of minute, coloured cellules. Nuclei 

 (favellffi) immersed in the frond, suspended beneath the membranous wall, simple, 

 containing numei'ous minute, densely packed spores, enclosed within a hyaline enve- 

 lope. Tetraspores roundish, cruciate, immersed in the surface cellules, dispersed. 



Rose-red Algae of a very delicate, membranaceo-gelatinous substance, cylindrical 

 or flattened, formed of a membranous coating, enclosing a thin watery gelatine, 

 through which a few articulated, branching and anastomosing filaments are dis- 

 persed. The branching is most frequently dichotomous, rarely pinnated ; often 

 proliferous, new frondlets springing irregularly from the sides of the old, especially 

 from wounded places. In fertile specimens the favellcc are generally equally dis- 

 persed in great numbers through every part of the plant. Several species from 

 various parts of the world have been described, of which I can as yet claim but two 

 as North American : viz. 



1 . Halymenia ligulata, Ag. ; frond gelatinoso-membranaceous, compressed or 

 flattish, linear and dichotomous or cuneately expanded and sub-|)almate, often pro- 

 liferous from the disc and margin. J.Ag.Sp. Alg. 2, jo. 201. Harv. Phjc. Brit, 

 t. 112. Halarachnion ligulatum, Kutz. Sp. Alg. p. 721. Ulva ligulata, E. Bot. t. 420. 

 U. rubra., E. Bot. t. 1627. 



Hab. Thrown up from deep water. Key West, a single specimen only. 

 W.H.H. (v. v.) 



The only American specimen of this variable plant that I have yet seen is four 



