the Colony of Western Australia. 553 



inches high, nearly a line in diameter, much branched, dichotomous, I'arely with lateral 

 branches. The peripheric threads extend beyond the calcareous portion, and form a purple 

 tomentum to the branches, as in Microthoe. This fine plant is named in compliment to 

 George Cheyne, Esq., of Cape Eiohe, at whose hospitable house I resided during my resi- 

 dence on that part of the coast. 



222. Microthoe ?api'(7escen.s, Dne.? Galaxaura lapidesceiis, hx.? Keefs at Eottnest (221). This 



is certainly a Rhodospcrm, and nearly related to Liagora. When living it is clothed with 

 dense, dark purple villosity, composed of Callithamnoid filaments. 



223. MiOKOTUOE marginata, Dne. ? On the reefs, at Rottnest, and cast ashore at King George's 



Sound (96). I have no authentic specimen at hand to compare with. Mine spring from 

 short, dichotomous, cylindrical, woolly stems, which, had they been found disconnected, 

 would pass for a separate species. The upper frond is flat, slightly inflexed at the margin 

 when dry, repeatedly dichotomous, and deep purple red. 



Order X RHODYMENIACEiE. 



224. Hymenocl.\dia? divaricata, n. sp. ; fronde plana rosea gelatinoso-membranacea decomposite 



pinnata, rachide flexuosa basi et apice attenuata, pinnis pinnulisque lineari-Ianceolatis 

 attenuatis patentibus, pinnulis ultimis setaceis minutis horizontali-divaricatis; cystocarpiis 

 ad discum vel marginem laminte insidentibus sparsis; tetrasporis magnis triangule divisis 

 per ramos majores distributis. King George's Sound (68). 1 venture to refer this plant 

 to Hpnenodadia, J. Ag., a genus founded on Fucus Usnea, R. Br., whose cystocarps are 

 unknown, and which is temporarily placed by J. Agardh in Laurenciacece. My plant has 

 a similar habit and internal structure, and similar tetraspores ; but the nucleus of its cys- 

 tocarp is formed of strings of cells radiating from a basal placenta; if I mistake not, on the 

 plan of those of a Rkocli/meniacea, though the spores are of unusually large size in this order, 

 and more resemble those of a Spharococcoid plant. The external habit is not unlike that of 

 Gigaiiina Teedii. 



225. Hymenocladia? Ravialina, n. sp. ; fronde plana rosea membranacea ramosissima, ramis sub- 



pinnatim 2-3-divisis alternis oppositisque patentibus basi et apice attenuatis, ramulis ulti- 

 mis subulatis v. filiformibus elongatis horizontaliter patentibus; fructu. . . . King 

 George's Sound, rare (87). A less gelatinous plant than the last, imperfectly adhering to 

 paper, more irregularly branched, less compounded, and with much longer ramuli. 



226. Plocamicm procerum, Ag. Very common everywhere (94). 



227. Plocamium Mertensii, Grev. Rottnest (140 and 259). 



228. Plocamium Pretssiamim, Sond. King George's Sound and Rottnest (86)- 



229. Plocamium coccineum, Lyngb. King George's Sound and Rottnest (72). 



230. Rhodophyllis bifiia, Kutz. Garden Island, rare (145). 



231. Rhodophyllis volans, n. sp.; csespitosa, e fills intertextis orta; fronde membranacea rosea 



subdichotoma vel vage partita, segmentis linearibus patentibus margine simplicibus vel 

 sffipissime pinnatis; pinnis ovalibus oblongisve obtusis basi attenuatis subpetiolatis; cysto- 



