NOTES ON FRESHWATER ALG/E. 337 



Hab. Cowside Beck, Arncliffe, W. Yorkshire. 



This occurred in large brilliant blood-red patches, covering 

 those stones and rocks which could not be displaced by the usual 

 rapidity of the current, and which are often left dry. Some few 

 cells had about a fourth part of the contents still green. 



38. Calothrix balearica Born. & Flah. var. tenuis, var. n. A 

 variety with the filaments only about half the thickness of those of 

 the type. The filaments are very tortuose and intricate, and hetero- 

 cysts are absent. Crass, trich. 3*5-5 {x. 



Hab. Simon's Fell, W. Yorkshire. 



39. Oscillatoria irrigua Kiitz. 

 Hab. Vehar Lake, Parel, Bombay. 



40. Clonothrix gracillima, sp. n. 0. trichomatibus angustis- 

 simis, alteratim pseudoramosis, nunquam attenuatis ; pseudoramis 

 flexuosis, elongatis et alternatim psudoramulosis ; vaginis tenuibus, 

 firmis, arctis et achrois ; cellulis diametro 3-4-plo longioribus ; 

 cytioplasmate l^te aBrugineo. Crass, trich. 1*5 /x. 



Hab. In horse-trough, Shipley, W. Yorkshire ; also Pilmoor, 

 near Thirsk, N. Yorkshire. 



The false ramification of this plant is most peculiar; the 

 apparent branches seem to be merely tangentially applied at their 

 bases to the primary filaments, and are of the same thickness. 

 The "branches" appear to arise by the lateral protrusion of a few 

 cells from the sheath, these cells remain attached laterally, and 

 grow quite independently into long flexible filaments. The cells 

 were often seen to have left the sheath, the latter being empty for 

 some distance. 



The only other species of this genus is C.fusca E. Eoze (Journ. 

 de Botanique, Oct. 1896, 329), from which it is distinguished by its 

 much narrower trichomes of uniform thickness, its more elongate 

 false-ramifications, and by its bright blue-green colour. We had 

 noticed this plant as belonging to a genus hitherto undescribed 

 some time before the publication of Clonothrix by M. E. Eoze. 



41. DactyloGoccopsis montana, sp. n. D. cellulis solitariis 

 vel in familiis 4-16 (circ.) associatis ; cellulis ellipticis, doliformi- 

 bus vel obliquis, cum polis attenuatis et leviter rotundatis ad 

 extremum, diametro circiter 2-3-plo longioribus ; cellulis familiarum 

 plerumque inter se distantibus, post divisionem approximatis ; cytio- 

 plasmate pallide serugineo. Long. cell. 8-6-11-5 /x ; lat. cell. 

 3-5-4 fi. 



Hab. Cowgill Wold Moss, Widdale Fell, and Keighley Moor, 

 W. Yorkshire. 



The form of the cells readily distinguishes this species from 

 D. rupestris Hansg. and D. rhaphidioides Hansg. It also has a 

 different habitat, and the families of cells, which appear to be 

 surrounded by a small amount of mucus, attain a somewhat larger 

 size than in either of the two species mentioned. The cell- walls 

 are very firm, and the division of the cells is in one direction only, 

 being somewhat oblique (as in Dactylococciis !). The chromatophore 



