NEW OR CRITICAL BRITISH MARINE ALG^. 437 



Berkeleyi that, were it not for the entire absence of any investing 

 gelatinous substance, one might feel tempted to consider the plant 

 the form of that species bearing plurilocular sporangia. The fila- 

 ments in the lower portion of the cushion are inextricably interlaced 

 in a manner very similar to that of Petrospongium ; the cells of the 

 free filaments, however, are cylindrical, not swollen in the middle 

 as in that genus. Hyaline hairs are scattered amongst the erect 

 free filaments. The ultimate ramuli are always secund, and usually 

 more or less closely pressed against the branch from which they 

 arise. The plurilocular sporangia are somewhat like those of A'. 

 confervoides, but longer, and always terminate in an obtuse point. 

 Like the ultimate ramuli they are very erect, and form a very acute 

 angle with the branch on which they are borne ; they are frequently 

 very numerous, most of the ultimate ramuli each bearing three 

 or four sporangia, secundly arranged, and springing from cells 

 contiguous to each other. 



13. Sphacella subtilissima Reinke, in Berlchten der Deutschen 

 Botanischen Gesellscha/t, Band viii. Heft. 7 (1890), p. 206, var. 

 ANGLicA, nov. var. Fronds forming minute tufts on Ralfaue and 

 HildenbrandticB, between the cells of which the lower portion of the 

 filaments penetrate. Vegetative characters like those of the typical 

 form. Unilocular and plurilocular sporangia borne on the same 

 individuals. Plurilocular sporangia cylindrical, slender, terminal 

 or intercalary, hardly broader than the filaments, from which they 

 are formed. Unilocular sporangia as in the typical form. Hab. : 

 Drake's Island, Plymouth, January, 1897, Geo. Brehner. 



Mr. Brebner's specimens of this plant agree well with Prof. 

 Eeinke's description and figures, with the single exception that 

 both plurilocular and unilocular sporangia are borne on the same 

 individuals. In form the plurilocular sporangia, which, I believe, 

 have never before been observed, are very like those of Leptonema, 

 and but slightly differentiated from the vegetative cells. After the 

 discharge of the spores, the supporting branch continues its growth 

 through the empty sporangium ; this happens in the case both of 

 unilocular and plurilocular sporangia. Mr. Brebner was of opinion 

 that his specimens should be referred to the genus Ectocarpus as a 

 now species, but spirit-material, especially the sporangia, show a 

 slight temporary blackening when treated with eau de Javelle, 

 which never happens in the case of any true Ectocarpus. This 

 temporary blackening under the influence of eau de Javelle, and the 

 apical growth, point to the plant being one of the Sphacellariacecc, 

 and I am unable to find any character by which it can be specifically 

 separated from Keinke's Sphacella subtilissima. , 



Floride^. 



14. Rhodochorton Brebneri, nov. spec. Primary filaments 

 decumbent, stragglingly branched, the branches usually widely 

 separated from one another, irregularly nodose, about 9 /a in 

 diameter, sunk in the substance of GUeosiphonia capillaris ; hairs 

 and fertile branches erect, projecting slightly above the surface. 

 Erect branches much and irregularly branclied, forming dense 



