553 
the Colony of Western Australia. 
inches high, nearly a line in diameter, much branched, dichotomous, rarely with lateral 
branches. The peripheric threads extend beyond the calcareous portion, and form a purple 
tomentum to the branches, as in Mierotlioe. This fine plant is named in compliment to 
George Cheyne, Esq., of Cape Eiche, at whose hospitable house I resided during my resi- 
dence on that part of the coast. 
222. Miceothoe Dne. ? Galaxaura lapidescens, 'Lx.t Eeefs at Eottnest (221). This 
is certainly a Rhodosperm, and nearly related to Liagora. When living it is clothed with 
dense, dark purple villosity, composed of Callitharanoid filaments. 
223. Microthoe marginata, Dne. ? On the reefs, at Eottnest, 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, rvoolly 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.— EHODYMENIACEiE. 
224. Hymenocladia? divaricata, n. sp. ; fronde plana rosea gelatinoso-membranacea decomposite 
pinnata, raohide flexuosa basi et apice attenuata, pinnis pinnulisque lineari-lanceolatis 
attenuatis patentibus, pinnulis ultimis setaceis minutis horizontali-divaricatis ; cystocarpiis 
ad discum vel marginem laminae insidentibus sparsis; tetrasporis magnis triangule divisis 
per ramos majores distributis. King George’s Sound (68). I venture to refer this plant 
to Hymenocladia, J. Ag., a genus founded on Fucus TJsnea, E. Br., whose cystocarps are 
unknown, and which is temporarily placed by J. Agardh in Laurenciaceai. 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 Rhodymeniacea, though the spores are of unusually large size in this order, 
and more resemble those of a Sphcerococcoid plant. The external habit is not unlike that of 
Gigartina Teedii. 
225. Hymenocladia? Ramalina, 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. Plocamidm procfiraw, Ag. Very common everywhere (94). 
227. Plocamidm Mertensii, Grev. Eottnest (140 and 259). 
228. Plocamium Preissianum, Sond. King George’s Sound and Eottnest (86). 
229. Plocamidm coccineum, Lyngb. King George’s Sound and Eottnest (72). 
230. Ehodophyllis bifida, Kiitz. Garden Island, rare (145). 
231. Ehodophyllis n. sp. ; cffispitosa, e fills intertextis orta; fronde membranacea rosea 
subdichotoma vel vage partita, segmentis linearibus patentibus margine simplicibus vel 
siepissime pinnatis; pinnis ovalibus oblongisve obtusis basi attenuatis subpetiolatis ; cysto- 
