THE FRESHWATER ALO E OF CEYLON, 141 
82. CLosTERIUM INCURVUM, Bréb. in Mém. Soc. Sci. Nat. Cherbourg, iv. 1856, p. 150, 
t. 2. fig. 47. 
Lat. 654; apicibus 34 u inter se distantibus. 
Hab. Paddyfields, Heneratgodha. 
83. CLOSTERIUM EXIGUUM, sp. n. (Pl. 18. figs. 17, 18.) C. minutum, valde arcuatum, 
cellulis angustis, sensim attenuatis polos versus, polis angustis acutis; membrana 
achroa glabra; pyrenoidibus in semicellula unaquaque 2; locellis apicalibus 
subterminalibus et corpuscula singula inclusa. 
Lat. 4:8-5:24; apicibus 79-82 u inter se distantibus. 
Hab. Paddyfields, Heneratgodha. 
This species is perhaps nearest to C. parvum, Naeg., var. angustum, West & G. S. West, 
but differs in its smaller size, in being narrower, in the greater attenuation of the poles, 
and in the nature of the apical locellus, which contains only one moving granule. 
It should be compared with C. Venus, Kuetz. 
Genus DocrprvM, Bréb. 
84. Docrprum BacuLUM, Bréb. in Ralfs, Brit. Desm. 1848, p. 158, t. 33. fig. 5. 
Long. 148-2804; lat. ad bas. semicell. 9:5-12:5 4; lat. ad med. semicell. 7:8-97 4; 
lat. ad apic. 4°8—6 u. 
Hab. Paddyfields, Heneratgodha. 
85. DOCIDIUM MANUBRIUM, West & G. S. West, in Trans. Linn. Soc., Bot. ser. 2, vol. v. 
1895, p. 44, t. 5. fig. 31. 
Var. TENUE, var. n. (Pl. 19. fig. 11.) Var. semicellulis angustioribus, lateribus parallelis; 
inflatione basali prominentiore; granulis (et plicationibus) 16 (visis 9) ad basin ut 
in forma typica. 
Long. 375,4; lat. ad bas. semicell. 224; lat. ad med. semicell. 184 ; lat. ad apic. 15 m. 
Hab. With the preceding species. 
Genus PLEUROT.ENIUM, Nag. 
86. PLEUROTENIUM NODOSUM, Lund. in Nov. Act. Sci. Upsala, ser. 3, viii 1871, p. 90. 
Docidium nodosum, Bail. in Ralfs, Brit. Desm. 1848, p. 218, t. 35. fig. 8. 
Hab. Paddyfield between Kosgoda and Urahaighasmahendai. 
87. PLEUROTÆNIUM Kayri, Rabenh. Flor. Europ. Algar. iii. p. 439.  Docidium Kayei, 
Arch. in Quart. Journ. Micr. Sci. 1865, p. 296, t. 7. fig. 2. Docidium horridum, 
Borge, in Bih. till K. Sv. Vet.-Akad. Handl. xxii. 1896, Afd. 3, no. 9, p. 28, t. iv. 
fig. 55. ` ; 
Long. 254-280 à; lat. bas. semicell. sine spin. 49-52, cum spin. 60-67 u; lat. apic. 
semicell. sine spin. 31-33 u, cum spin. 40-42. (PI. 18. figs. 33, 34.) 
Hab. With the preceding species. : 
X 
