436 NEW OR CEITICAL BRITISH MARINE ALG^. 



parasite, and gave to it the name Streblonema (equale. Dr. Kuckuck 

 has recently removed it on account of the peculiar form of the 

 plurilocular sporangia to his genus PhcBostroma. Specimens of this 

 species are contained in fasc. ix. of Mr. Holmes's Alg. Exsicc. 



9. Ph^ostroma prostratum Kuck. in Bot. Zeit. 1895, p. 185. 

 [Phaocladia prostrota Gran. Algeveg. Tonshergfjorden.) I refer to 

 this species a few specimens of a Phccostroma which I gathered at 

 Cumbrae in 1891- The fronds are not nearly so much branched 

 as in P. pustulosum, and form a much more open layer. The 

 plurilocular sporangia, which are formed, as in P. -pustulosum, 

 from cells in the continuity of the filaments, are hardly larger than 

 the vegetative cells, and consequently are only very slightly raised 

 above the surface of the layer ; they are frequently very numerous, 

 all the cells of a branch being not unfrequently transformed into 

 sporangia. 



10. MiKROSYPHAR PoRPHYR^ Kuck. Bemevk. zur Mar. Algeveg. 

 von Helgoland ii. I.e. p. 381. Folkestone, June, 1896, E. A. B. 

 This minute species forms yellowish brown stains, which to the 

 naked eye are not unlike the young fronds of Myrionema strangulans 

 on old fronds of Porplvjra laciniata. The thallus is composed of 

 slender, densely branched, creeping filaments, which are entirely 

 immersed in the substance of the host-plant. The plurilocular 

 sporangia, which differ but little in form and size from the vegetative 

 cells, push their way to the surface of the host-plant, rising slightly 

 above it. 



11. MiKROSYPHAR PoLYsiPHONi^ Kuck. l.c. p. 381. Bcrwick, 

 June, 1895, E. A. B. This species, which differs but little, except 

 in the size of the cells, from M. Porphyry, is frequently found in 

 the cell-walls of P. urceolata and C. j^olyspemmm ; in general 

 appearance it resembles Endodenna viridis, except in colour and, of 

 course, in fructification. 



12. Ectocarpus Microspongium, nov. spec. Fronds minute, 

 forming yellowish-brown, compact, hemispherical, cushion-like 

 patches about 1 mm. in diameter on the fronds of RalfsicB. Fila- 

 ments much branched, irregularly nodose and inextricably matted 

 together below, cylindrical and free above. Branching irregularly 

 dichotomous and spreading below, secund and erect above. Cells 

 9-15 /A in diameter and 9-12 /x long. Plurilocular sporangia often 

 very numerous, arranged secundly on the upper free branches, 

 oblong-lanceolate in form, 70-105 /x long by 12-15 p. wide, sessile, 

 or borne on very short one- or two-celled stalks. Long colourless 

 hairs present on the upper branches. Hab. : Redding Point and 

 Drake's Island, Plymouth, September, 1896, Geo. Brehner. 



This interesting species appears to be quite distinct from any 

 described Ectocarpus. The minute cushion-like fronds are either 

 isolated or collected into groups, one frond pressing closely against 

 another, but never losing its hemispherical form. To the naked 

 eye the plant exactly resembles Microspongium gelatinosum, or very 

 mhiute specimens of Petrospongium Berkeleyi. Sections made 

 through one of these cushions so greatly resemble those of P. 



