THE FRESHWATER ALGJE OF CEYLON. 137 
Genus CrosTEnIUM, Nitzsch. 
58. CLOSTERIUM SUBCOMPACTUM, sp. n. (Pl.18.fig. 11.) C.subparvum, cellulis diametro 
31-9$-plo longioribus, subrectis, leviter attenuatis polos versus, dorso modice 
convexo, ventre subrecto, polis crassis truncato-rotundatis, levissime dilatatis et 
cum nodulo late incrassato, in medio cellularum levissime constricto ; membrana 
glabra achroa; pyrenoidibus 2-3 in semicellula unaquaque. 
Long. 99-100 4 ; lat. 29-314; lat. apic. 15-18 u. 
Hab. Paddyfield between Kosgoda and Urahaighasmahendai. 
This species somewhat resembles C. compactum, Nordst. (in K. Sv. Vet.-Akad. Handl. 
xxii. 1888, no. 8, p. 68, t. 3. fig. 25), but is smaller, less curved, and has much broader 
and differently-formed apices. The median constriction is also peculiar. 
It might also be compared with C. Legumen, West & G. S. West (in Journ. Linn. 
Soc., Bot. xxxiii. 1897, p. 158, t. 8. figs. 5-7), a species known from Singapore and West- 
Central Africa; it is distinguished by being relatively shorter and more robust, by the 
thieker and slightly dilated apices, and by the median constriction. 
59. CLOSTERIUM STRIOLATUM, Ehrenb.; Ralfs, Brit. Desm. p. 170, t. 29. fig. 2. 
Long. 264-277 u; lat. 22-23 u; lat. apic. 9-10°5 pu. 
Hab. Paddyfields, Heneratgodha. Paddyfield between Kosgoda and Urahaighasma- 
hendai. 
Var. ROBUSTUM, var. n. (Pl.18.fig. 13.) Var. robustum, cellulis crassioribus, diametro 
7-8-plo longioribus, apicibus crassioribus triangulo-rotundatis; membrana crassa, 
striis validis 14 (visis). 
Long. 201,4; lat. 26 u; lat. apic. 12:5 u. 
Hab. Paddyfields, Heneratgodha. 
60. CLOSTERIUM INTERMEDIUM, Ralfs, Brit. Desm. 1848, p. 171, t. 29. fig. 3. 
Long. 2344; lat. 204; lat. apice. 1075 u. 
Hab. Paddyfields, Heneratgodha. 
61. CLOSTERIUM ANASTOMOSUM, sp. n. (Pl.18. figs. 24-26.) C. submediocre, cellulis 
diametro 21—24-plo longioribus, levissime curvatis, lateribus subparallelis, levissime 
attenuatis polos versus, polis subrotundo-truncatis (indistincte subdilatatis); mem- 
brana luteo-fuscescente, delicate striolata, striis paucis irregulariter anastomosis ; 
pyrenoidibus in serie unica in semicellula unaquaque 7-10; locellis apicalibus 
terminalibus et corpusculis 2-3 includentibus. 
Long. 217-284 p; lat. 10:5-12 p ; lat. apic. 75-95 p. 
Hab. Paddyfields, Heneratgodha. 
This plant most nearly approaches C. Toro», West, but is distinguished by its greater 
robustness, its less attenuated cells, the colour and remarkable striolation of the cell-wall. 
It may also be compared with C. Ulna, Focke (— C. directum, Arch.). 
