Ser. Rhodosperme^. Fam. CeramiacecB. 



Plate LXXIX. 



HALOPLEGMA PREISSII, Sond. 



Gen. Char. Frond sponge-like, expanded, wholly composed of interwoven 

 and anastomosing confervoid filaments ; the central filaments longitu- 

 dinal, subparallel, anastomosing; the superficial short, vertical, and 

 free. Fructification : 1, involucrated favellse, sessile on the network ; 

 2, tripartite tetras^ores, borne on the superficial filaments. — Halo- 

 PLEGMA {Mo7d.), from aX?, the sea, and Trkc'yfia, a network, or 

 woven substance. 



Frons spongiosa, expansa, fills confervoideis intertextis anastomosantihisque con- 

 texta ; fills interiorlbus longitudinalihis siibparallelis anastomosantibus, exteri- 

 orib'us liberis verticalibus brevlbus. Fruct. : \,favell(jeinvolucrataadfi-on- 

 dem sessiles ; 2, tetrasporee triangule dlvisa, pedicellatce, ad ramulos afiixcB. 



Haloplegma Preissii ; frond somewhat flabelliform, subdichotomous, laci- 

 niated ; the segments pinnatifid ; pinnules oblique, falcate, fringed on 

 the outer edge ; articulations of the filaments 2-3 times as long as 

 broad. 



H. Preissii; fronde flabelliformi subdlchotomo-laclniata ; laciniis pinnaiifidls 

 scepe secundis ; pimmlls obliquls falcatis extus fimbriatls ; artlculls filarum 

 diametro 2-S-plo longloribus. 



Haloplegma Preissii, Sond. PI. Prelss. v. 3. jo. 171. Kiitz. Sp. Alg.p. 672. 

 /. Ag. Sp. Alg. v. 2. p. 111. Harv. Alg. Aiistr. Exslc. n. 489, 490. 



Rhodoplexia Preissii, Harv. in Hook. Ic. Fl. t. 613. 



Hab. Western Austraha, Preiss, Brummond, etc. Common at Premantle, 

 Rottnest, and King George's Sound; also on many parts of the 

 southern coast. Port Phillip Heads, and Western Port, W. H. H. 

 Tasmania, R. Gunn. In the Tamar, above Georgetown, Rev. I. Fere- 

 da^, etc. 



Geoge. Distr. Western and southern coasts of Australia. Tasmania. 



Descr. Root a mass of woolly filaments. Frond a flat, sponge-like or cloth-like 

 body, very irregular in shape, 3-12 inches long, and as much in expansion 

 of the segments. The form is so greatly varied that it is difficult to de- 

 scribe, except in general terms. The outhne, when young, is generally fla- 

 belliform, and in some specimens this form is retained, the fan being but 

 slightly cleft into a few shallow segments : in others the frond is dichotomo-; 

 multifid, the main branches not more than i inch wide, or even less J 

 the lesser ones deeply pinnatifid or bi-pinnatifid. In other specimens the 

 lesser branches are deeply lobed on one edge only. AH the axils are rounded. 



