V. CRYPTONEMIACEiE. 193 



inches long, about five inches in the spread of the lacinife, flabelliform, sub-fasti- 

 giate, repeatedly and pretty regularly dichotomous, the larger divisions a third of an 

 inch wide, the upper gradually narrower, and the ultimate ones a line or less in 

 width ; apices acute. Substcmce, membranaceo-gelatinous. Colour, a fine, clear, 

 pinky red. It closely adheres to paper in drying. 



2. Halymenia Floresia, Ag. ; frond gelatino-raembranaceous, flat, stipitate, elon- 

 gate, pinnately-decompound ; pinnte and pinnules linear, acuminate, acute, patent, 

 entire or serrato-ciliate. J. Ag. Sp. Alg. 2, p. 205. Kiitz. Sp. Alg. p. "JIG. Fucus 

 Floresius, Turn. Hist. t. 256. 



Hab. Thrown up from deep water. Key West, rare, W. H.U. {QQ), Dr. 

 Blodgett. (v. v.) 



Boot a small disc. Fronds solitary or slightly tufted, six to eight inches long, 

 and as much in the expansion of the lacinia-, somewhat ovate in outline, flat, and 

 very thin, decompound-pinnatifid. Sometimes the main frond (or rachis) is two or 

 three inches wide, with the margin cut into very densely crowded, bi-pinnatifid 

 lobes, half an inch wide and two or three inches long ; sometimes the frond is much 

 more deeply laciniated, the rachis and principal lacinia3 not more than half an inch 

 wide ; the laciniaj once, twice, or thrice compounded ; the secondary ones one or 

 two lines wide, and margined with subulate, tooth-like processes. Axils rounded ; 

 apices all acute and attenuated. Colour, a beautiful rosy-red. Substance delicately 

 gelatino-membranaceous. In drying it adheres most closely to paper. 



An extremely handsome plant. The Key West specimens, here described, closely 

 agree with the Mediterranean ones in Herb. T. C. D. Some are very broad, others 

 narrow. 



XVIII. HALOSACCION. Kutz. 



Frond cylindrical or obovate, simple or proliferously branched, hollow, the walls 

 formed of two strata of cells ; the inner stratum of two or more rows of roundish- 

 angular cells, the outer of oblong, vertically-seriated, coloured cellules. Concep- 

 tacles (unknown). Tetraspores cruciate, dispersed among the cortical cells. 



Until the conceptacular fruit of this genus shall be discovered, its proper position 

 must be considered doubtful. It is almost entirely constituted of Algaj from the 

 higher latitudes of the Atlantic and Pacific, and includes two distinct groups, each 

 characterised by differences of outward form, and by habitat. The Pacific species 



VOL. IV.— AET. 5. C C 



