THE FRESHWATER ALGJE OF CEYLON. 191 
Var. NANUM, Wille, in Vid.-Selsk. Forhandl. Christiania, 1880, no. 11, p. 46, t. 2. fig. 31. 
Long. 19 u; lat. cum proc. 31; lat. isthm. 48 u. | 
-Hab. Pond, Royal Botanical Gardens, and in artificial tank, Peradeniya. 
Var. sUBORNATUM, Schmidle, in Engler's Bot. Jahrbüch. xxvi. 1898, p. 51, t. 4. fig. 1. 
Long. 30 u; lat. cum proc. 63,4; lat. isthm. 9:5 u. 
Hab. In artificial tank, Peradeniya. 
Var. ELEGANTULUM, var.n. (Pl. 22. fig. 20.) Var. minor, corpore angustiore ; processibus 
leviter incurvatis, marginibus minutissime et acute nodulosis. 
Long. 23 4; lat. cum proc. 36; lat. isthm. 44 u. 
Hab. In artificial tank, Peradeniya. 
266. STAURASTRUM TAUPHORUM, sp. n. (Pl. 22. figs. 23-25.) S. mediocre, circiter 
1$-plo latius quam longum (cum processibus), modice constrictum; semicellule 
campanulatz basin versus, sursum multe expanse, apicibus latis et levissime 
concavis, angulis superioribus in processus longos horizontaliter dispositos productis, 
margine superiore processuum dentato cum dente maximo ad basin, margine inferiore 
leviter undulato, apicibus processuum quadridentatis; a vertice visse triangulares, 
lateribus leviter concavis, angulis in processus longos productis, marginibus lateral- 
ibus processuum levissime undulatis ; ad basin semicellularum sub processu magno 
unoquoque eum processu parvo glabro profunde et late bifureato (T-forma), brachio 
unoquoque retrorsum curvato et bidentieulato. 
Long. 49-56 u; lat. cum proc. 73-96 u; lat. sine proc. circ. 23-274; lat. isthm, 
7-15 u. ; 
Hab. Paddyfields, Heneratgodha. 
` The chief peculiarity of this extraordinary Staurastrum consists of the small processes 
situated at the base of the semicells immediately underneath the large spreading 
These small processes are three in number, quite smooth, and are suddenly 
processes. 
Each arm is of uniform 
divided into two widely spreading, gracefully curved arms. 
thickness with the main process, but a little longer, and the whole whorl is disposed in 
a horizontal plane. Numerous specimens were examined, and all possessed precisely the 
same characters. 
The teeth on the upper margin of the large processes, which gradually diminish in 
size towards their apices, are also characteristic; and, in addition, few Staurastra are 
known with the apices of the processes quadridentate. 
Genus ARTHRODESMUS, Ehrenb. 
267. ARTHRODESMUS OCTOCORNIS, Ehrenb. Infus. 1838, p. 152; Archer, in Pritch. Infus. 
ed. 4, 1861, p. 736, t. 1. fig. 30. Xanthidiwm? octocorne, Ralfs, Brit. Desm. 1848, 
p. 116, t. 20. fig. 2 a-e. 
Hab. Paddyfields, Heneratgodha. 
