the Colony of Western Australia. 563 



simis arcuato-incurvis obtusis; articulis omnibus diametro 2-3-plo-Iongiorlbu3; tetrasporis 

 ellipsoideis numerosis secus pinnas sessilibus. Crevices of rocks, at half-tide, Rottnest 

 (328). This is certainly near C. roseum ia miniature. To the naked eye it looks very like 

 Dasya ocel/ata, or like a bunch of little bottle brushes. 



309. Callithamnion (/eJj'fe, n. sp. ; fronde pusilla (vix unciali) tenuissima ecorticata Cicspitosa in- 



ferne quoquoversum superne distiche ramosa ; ramis paucis alterne divisis, ramis minoribus 

 disticheramulosis, ramulis paten tissimis inferioribus simplicibus spinffiformibus superioribus 

 furcatis v. subpinnulatis; articulis inferioribus diametro o-8-plo, ramulorum 3-4-plo-longi- 

 oribus ; tetrasporis solitariis ad ramulos sessilibus. Rottnest, rare (330). Unlike any Aus- 

 tralian species; and most like some starved form of C. pulyspermum, but of a very fragile 

 substance and pale colour. 



310. Callithaunion radicaiis, n. sp.; nanum, parasiticum, velutino-casspitosum ; fronde minuta 



(2 lineas alta) basi fibrillis crispatis radicante, e basl ramosissima; ramis primariis alternis 

 secundisve 2-3-ties decompositis, minoribus ramulisque secundis strictis; articulis cylindra- 

 ceis diametro 4-o-plo-longioribus; ramulis fructiferis prope basin ramorum sparsis sirapli- 

 cibus y. parum ramosis; tetrasporis ellipsoideis terminalibus. Oa Zostera leaves, Fremantle 

 (331). This resembles C. luxurkins, J. Ag., externally, but seems sufEciently marked by 

 its rooting filaments and longer articulations. 



311. Callithamnion bolrijocarpum, n. sp. ; nanum, penicillato-cffispitosum; fronde minuta (l-lj 



lineas alta) e basi ramosissima, ramis alternis v. secundis patentibus flexuosis nunc sub- 

 squarrosis; articulis diametro 4-plo-longioribus; tetrasporis magnis triangule divisis in glo- 

 merula ad axiles ramorum densissime aggregatis; antheridiis, botryoideis e quoque fere 

 articulo ramorum sa;pe evolutis. Abundant on Chorda loiaenlaria, at King George's Sound, 

 in August (324). Externally very like C Daviesii, but I suppose distinctly characterized 

 by its fruit. The tetraspores are very large for this section of the genus. The antheridia 

 resemble little clusters of grapes, ranged along the upper branches of fertile specimens. 



312. Callithamnion c<y)a?-s!nn, Harv,(?) Parasite on Sporoc/nms, at Garden Island. This requires 



to be compared with British specimens; and also with Kutzing's C.huniile from the Cape of 

 Good Hope. It is quite diiferent from either of the preceding, very sparingly branched, of 

 a deep purple colour, and rather rigid texture, with very short articulations. 



Series III.— CHLOROSPERME^. 



Order I SIPHONACEiE. 



313. C.KV1.Y.-RV A. simpliciuscula,Ag.l On the reefs,'Rottnest. A much dwarfer, and more branching 



form than that figured by Turner, if the same. Possibly my plant may be rather akin to 

 C. lend/era, J. Ag. (207). 



314. Cavlekfa latevirens, Mont.? Extremely abundant on the surface of shallow reefs, exposed 



at low water, Rottnest. I have not compared with Montagne's plant (208). 



315. Caulerpa cylindracea, Sond. King George's Sound, rare (.54). 

 VOL. XXII. 4 D 



