fënd mr Ge re EE 
e OT 
THE FRESHWATER ALG OF CEYLON. 167 
175. CosMARIUM AMERICANUM, Lagerh. in Ofvers. K. Sv. Vet.-Akad. Fórh. 1885, no. 7, 
p. 240, t. 27. fig. 14. Cosmarium coliferum, Lagerh. in Bih. K. Sv. Vet.-Akad. 
Handl. xiii. 1888, Afd. 3, no. 9, p. 7, t. 1. fig. 5. 
Long. 21-23 »; lat. 14-19 n; lat. isthm. 4°4-5-7 u; crass. 9'7 un 
Hab. With the preceding species. 
Numerous forms of this species were observed, and they exhibited great variability of 
outline. Most of the examples more nearly approached the figure of C. coliferum than 
that of C. americanum, and some of them had the sinus more closed. In all cases there 
was a large yellowish thickening of the cell-wall in the centre of the semicells. 
176. CosMARIUM SULCATUM, Nordst. Alg. Sandvic. 1878, p. 13, t. 1. fig. 18. 
Var. INCRASSATUM, var. n. (PI. 20. figs. 36-38.) Var. cellulis profundissime constrictis, 
semicellulis in centro incrassatis et luteolis; a vertice visis ellipticis, incrassatis ad 
medium utrobique; a latere visis late ellipticis, lateribus incrassatis. 
Zygospora globosa, glabra. 
Long. 25°5-32°5 u; lat. 19-26 u; lat. isthm, 3:8-5'7 u; crass. 10:5-15 u: diam. zygosp. 
34-35 n. 
Hab. With the preceding species. 
This peculiar variety is thickened in the middle of each semicell instead of possessing 
the undulations of the typical plant. 
177. CosMARIUM CONTRACTUM, Kirch. Krypt.-flora Schlesien, Alg. 1878, p. 147. 
Long. 37 »; lat. 28 u; lat. isthm. 6 n. 
Hab. With the preceding species. 
178. CosMARTUM AVERSUM, West & G. S. West, in Trans. Linn. Soc., Bot. ser. 2, v. 1895, 
p. 70, t. 8. figs. 6, 7. 
Long. 31:5 u; lat. 22 u; lat. isthm. 5°3 m. 
Hab. With the preceding species. 
179. CosMARIUM GLOBOSUM, Buln. in Hedwigia, i. 1861, p. 52, t. 9. fig. 8. 
Var. WoLLEI, West & G. S. West, Z. c. 1896, p. 252, t. 15. fig. 17. : 
Forma membrana crassa et scrobiculata. Long. 40 u; lat. 32 4; lat. isthm. 29/5 p. 
(P1. 20. fig. 42.) 
Hab. With the preceding species. 
Perhaps this plant may be a distinct species. 
180. CosMARIUM MONILIFORME, Ralfs, Brit. Desm. 1848, p. 107, t. 17. fig. 6. Tessar- 
thonia moniliformis, Turp. 
Hab. With the preceding species. 
181. CosMARIUM PSEUDOCONNATUM, Nordst. in Vidensk. Medd. f. d. natur. Foren. 
Kjobenhavn, 1870, p. 214, t. 3. fig. 17. 
