8 SOME NEW BRITISH MARINB ALdM, wide. There are from 1 to 6 or more cells in the width of the frond. In K. investiens there are never more than 2 cells in the width of the filament. From Bangia cilians it is easily distin- guished by its monostromatic frond. Colaconema, nov. gen. Thallus microscopic, consisting of rose-red, creeping, irregularly branched, jointed filaments, living in the cell-walls of various algae. Filaments often anastomosing, sometimes loosely united laterally. Monosporangia formed from portions either of the terminal cells of the principal axes, or of short swollen 1- or few-celled lateral branches, or even from a portion of a cell in the continuity of the filament. The undifferentiated portions of the cells forming cup-like bases for the sporangia. C. Bonnemaisoniae, nov. sp. Filaments flexuous, much and irregularly branched, anastomosing so as to form an irregular net- work between the cortical cells of the host-plant. Cells very variable in shape, simple, furcate, cruciate or irregular, swollen here and there, varying in length from one to six or eight, or even more times longer than broad, usually 3-6 /x in diameter. Spo- rangia lateral, nearly globular, 9-12 ^ in diameter, usually in clusters of from 2 to 6, cup-like base conspicuous, about one-third the size of the sporangium. Growing in the cell-wall of Bonnemaisonia asparagoides. Plymouth, Sept. 1895, G. Brebner. Berwick-on- Tweed, E.A.B. C. Chylocladiae, nov. sp. Filaments slender, straight or very slightly flexuous, subsimple or sparingly branched, two filaments sometimes united by one or more lateral branches ; cells nearly cylin- drical, very long, often eight to ten or twelve times longer than broad, 2-5-3 [X in diameter; sporangia terminal or lateral, oval, 6-8 /a long by 4-6 /x wide, cup-like base of sporangium not conspicuous. In the cell- wall of Chylocladia ovalis, Torquay, E.A.B. Plymouth, Sept. 1895, G. Brebner. C? reticulatum, nov. sp. Filaments much and irregularly branched, anastomosing so as to form a more or less regular net- work between the cells of the host-plant ; owing to the very limited space in which they grow, the side branches are frequently so closely pressed against the principal branches that they appear to form one filament, composed of a double row of cells. Cells short, angular, about as long as broad or a little longer, 6-8 fi in breadth. Sporangia unknown. In the cell- wall of Desmarestia Dudresnayi. Moville, North Ireland, Oct. 1852, coinm. Dr. D. Robertson. Ply- mouth, Oct. 1895, G. Brebner. Montague describes and figures Callithamnoid filaments as part of his Desmarestia Gay ana (vide Ch. Gay, Histoire de Chile, viii. p. 242, Atlas Pars. Crypt, tab. xiv. fig. 1), and it is far from improbable that the plant described above is related to the parasite mistaken by Montagne for part of the Desmarestia. I am indebted to Mr. George Brebner, who did such excellent algological work at Cumbrae in 1893, and is now with equal success investigating the Marine Algae of Plymouth Sound, for beautiful specimens of C. Bonnemaisonim and C. ChylocladicB^ both species bearing monospores. The former, when I received it from Mr. Brebner, was quite new to me, although I afterwards
