BATRACHOSPERMES. 293 
“The articulations, or internodes, may be compared to reversed cones, 
the superior part or whorls being formed of a few short, simple subu- 
late filaments, which are not beaded; in these filaments the colouring 
matter chiefly resides, and it is amongst them that the glomerules are 
formed ; that portion of each articulation which is below the whorl is 
transparent, and beautifully exhibits the tubular and jointed structure 
of the layers which invest the primary cells in all the species of the 
genus Batrachospermum ; from many of these tubes short branches are 
given off, which have almost the appearance of scales.’"—Hassall. 
var, Dillenii. Bory. Ann, de Mus, Xx., t. 22, f. 2. 
Filaments dark brown, very thin, lower nodes remote, the 
interstices beset very densely with prominent cells, upper nodes 
crowded, branchlets very short, consisting of 3-4 cellules, ex- 
treme apical nodes confluent. 
Size. Cellules 012 mm. diam. 
Lemanea Dillenii, Bory. Ann, de Mus. xx., 23. 
Batrachospermum vagum, e. Dillenit, Rabh. Alg. Eur. iii., 
407. 
Conferva fontana nodosa, lubrica, nigris, Dill. Muse. t. 2, f. 
46. 
This is usually considered as a variety of B. vagum, but it seems more 
closely allied to B. atrum, if that be really a distinct species, 
Plate CXXVI. jig. 2. Portion of filament X 200 diam. 
Genus 120, THOREA. Bory. (1808.) 
Thallus filamentose, attenuated at the apex, branched, purple- 
brown, villose, mucous, with a solid central medullary stratum, 
surrounded by dichotomously divided branchlets.—Sur un genre 
nouveau de la Cryptogamie aquatique, nommé Thorea. 
Thorea ramosissima. Bory Ann. Mus. xx. 127. 
From a hand’s-breadth to a foot long, and rarely two feet, 
very much branched, about the thickness of a horsehair, dark- 
green, of a beautiful purple-violet when dry, ramelli spreading 
horizontally, long and short alternating, articulate; joints 1-3 
times as long as broad, or twice that length. 
Harv. Man. 120. Hass. Alg. 65, t. 16, f. 3-4. Rabh, Alg. 
Eur. iii. 
Batrachospermum hispidum, De Cand. FI. Fr. ii., 60. 
Attached to wood, &c. Walton-on-Thames. 
Plate CXXVII. fig. a. Small plant, natural size ; 0, ramuliand spore; 
c, portion of filament x 400. 
