THE FRESHWATER ALGZ OF CEYLON. 185 
apicibus truncato-obtusis; a vertice vise triangulares, lateribus leviter concavis, 
angulis in processus longos graciles valde curvatos dextram versus (ut in 5. eyrtocero) 
productis; processibus alterius semicellulze cum iis alterius alternantibus et curvatis 
in directione opposita. 
Long. 13 4; lat. sine proc. 9 4, cum. proe. 494; lat. isthm. 5 y. 
Hab. Paddyfields, Heneratgodha. 
The peculiar nature and the extraordinary curvature of the processes of this Staur- 
astrum sufficiently distinguish it. 
248. STAURASTRUM BIORDINATUM, sp. n. (Pl. 21. fig. 36.) S. parvum, paullo latius 
quam longum (cum processibus), modice constrictum; semicellulr latissime cyathi- 
formes, ad basin rotundo-bulbosxe annulatim plicatæ, angulis superioribus in pro- 
cessus breves validos leviter inflexos productis ex basi latissima, processibus sparse 
dentieulatis apicibus truncato-emarginatis, apicibus semicellularum convexis verrucis 
spinulato-emarginatis 6 prwditis; a vertice vise triangulares, lateribus concavis, 
angulis in processus breves emarginato-truncatos productis, verrucis emarginatis 4. 
ad marginem unumquemque et verrucis spinulato-emarginatis 6 intra marginem 
unumquemque (maximis in medio). 
Long. 274; lat. 32:5-34,; lat. isthm. 10 u. 
Hab. ln stream, Victoria Park, Colombo. 
249. STAURASTRUM POLYMORPHUM, Bréb, in Ralfs, Brit. Desm. 1848, p. 135, t. 22. fig. 9, 
t. 84. fig. 6. 
Long. 214; lat. cum proc. 22,4; lat. isthm. 6 4. 
Hab. On rocks, Mahawelli Ganga. 
Forma cum annulo granulorum parvorum circa basin ad 5S. basidentatum, Borge, 
accedens, sed minor. Long. 20,4; lat. cum proc. 224; lat. isthm. 6 y. 
Hab. Paddyfield between Kosgoda and Urahaighasmahendai. 
250. STAURASTRUM IOTANUM, Wolle, 1884; Desm. U.S. p. 137, t. 51. figs. 5-7; West & 
G. S. West, in Journ. Linn. Soc., Bot. xxxiii. 1898, p. 515, t. 18. figs. 14, 15. 
Hab. Paddyfields, Heneratgodha. 
251. STAURASTRUM TETRACERUM, Ralfs, 1845; Brit. Desm. 1848, p. 137, t. 23. 
fig. 7. 
Hab. With the preceding species. 
252. STAURASTRUM PSEUDOTETRACERUM, West & G. S. West, in Trans. Linn. Soc., ser. 2, 
Bot. v. 1895, p. 79, t. 8. fig. 39. S. contortum, Delponte, var. pseudotetracerum, 
Nordst. in K. Sv. Vet.-Akad. Handl. xxii. 1888, no. 8, p. 50, t. 5. fig. 14. 
Long. sine proc. 13 u, cum proc. 19-23 4; lat. cum proc. 19-214; lat. isthm. 5'8 a. 
Hab. With the preceding species. 
