174 CALLITHAMNION. 



On other Algae, generally on the stems of Laminaria aigitata, rare. 

 Bantry Bay, Miss Hutchins. Appin, Capt. Carmichael. Malbay, W. H. H. 

 Stems rising from creeping fibres, a quarter to half an inch in height, either 

 simple or divided into a greater or less number of alternate, or sometimes 

 opposite branches, which are naked below, their upper half pectinato-pinnate. 

 PinncB opposite, short or long, simple, very erect. Tetraspores globose, 

 with wide borders, stalked or sessile, sometimes clustered, often terminating 

 the pinnulae. Joints of the stem and branches 2 4 times longer than 

 broad. Colour a full rose-red. Nearly allied to C. Turneri, but much 

 smaller and with shorter joints. 



Section 2. FRUTICOSA. Main stems robust, opake, or nearly 

 opake, sub-simple, filled with longitudinal (rootlike) fila- 

 ments. Ramuli alternate (sp. 8 13). 



8. C. Arbuscula, R. Br. ; stems naked below, robust, car- 

 tilaginous, main branches set with shorter branches, which 

 are densely clothed on all sides with minute, imbricated, pin- 

 nated ramuli (or plumules) ; ultimate pinnules simple or 

 forked, recurved, acute, their joints twice as long as broad ; 

 tetraspores lining the inner faces of the pinnules. Harv. in 

 Hook. Br. Fl. ii. p. 340 ; Harv. Phyc. Brit. t. cclxxiv. Con- 

 ferva Arbuscula, R. Brown ! Dillw. t. 85 ; E. Bot. t. 1916. 



Dasya spongiosa, Ag. 



On rocks and stones between tide-marks. Perennial. Common on the 

 northern and western shores of Scotland and Ireland. Very rare on the 

 eastern shores of Scotland. Frith of Forth, Drs. Greville and Arnott. 

 Aberdeen, Dr. Dickie. Stem cartilaginous, inarticulate, as thick as a crow- 

 quill at base, 38 inches long, shaggy with fibres, but destitute of branches 

 below, divided above, the branches set with a second and third series similar 

 to themselves, but shorter, the smallest about two lines long ; all quadrifari- 

 ous, and densely clothed on all sides with minute, pinnated ramuli or plu- 

 mules. These latter are not a quarter of a line long, simply pinnate, the 

 pinna? long, subulate, very patent or falcato-reflexed. Articulations of the 

 ramuli once and a half or twice as long as broad. Tetraspores spherical, 

 with wide borders, lining the inner face of the ramuli. Favellce roundish 

 or lobed, mostly in pairs. Colour a very dark vinous red. Substance of 

 the stem cartilaginous, of the ramuli flaccid. This is the original Conferva 

 Arbuscula of Brown, whose specimens I have examined. The figure in 

 Eng. Bot. is not very characteristic : that of Dillwyn is better, except the 

 colour, which is far too bright. 



9. C. Brodi&i, Harv. ; stem sub-opake, veiny, obscurely 

 jointed, slender, simple, furnished throughout with patent, 

 alternate branches, which bear at each joint short, quadrifa- 

 rious, secondary branches, with a narrow, hastate outline ; 

 secondary branches laxly set with short, quadrifarious plu- 

 mules ; ultimate pinnules erecto-patent, obtuse, sub-simple ; 

 tetraspores roundish, sessile near the tips of the pinnules, 



