Freshwater Algee of S. of England . By W. & G. S. West. 485 
Genus Cosmarium Corda. 
1. C. quadratum Ralfs. I. Ep. III. Bh., Mp., Pu., Th., Wi. 
IY. Ks. Y. Go. YIN. YIII. G., T., W. 
2. C. Nymannianum Grun. III. Th. 
3. C. Hammer i Reinsch. YIII. G. 
4. C. granatum Breb. I. Ep. III. Fg., Rp. IY. Ks. YI. N. 
YII. D. YIII. K. 
Yar. subgranatum Nordst. I. Ep. III. Ep. YII. S. 
5. G. trilobulatum Reinsch. YI. N. 
6. C. tetragonum (Nag.) Arch. I. Ep. 
7. C. Cucumis Corda. I. Ep. Ill Ea., Mp., Pu. Y. Go. 
YIII. H., P. 
*8. C. subcucumis Schmidle (in Berichte der Naturf. Gesellsch. 
Freiburg, Bd. vii., Heft 1, p. 98, t. iv. f. 20-22). 
The forms seen were relatively longer and the sinus was rather 
more open. There were two large pyrenoids in each semi-cell. The 
relative proportion of breadth to length in Schmidle’s specimens was 
1:1* 42 ; that of ours was 1:1*79. 
Long. 64-77 y; lat. 38-44 y; lat. isthm. 13*5-18 y ; 
crass. 25-27 y. III. Ew. (abundant Feb. 1894), Wi. 
9. C. Balfsii Breb. III. C. YII. D. 
10. C. pachydermum Lund. III. M., Mp. YIII. Tm. 
11. G. canaliculatum West & G. S. West. Y. Go. 
12. G. pyramidatum Breb. III. Bi., C., Rp., Th. YII. D., Gp. 
YIII. G. 
13. G. pseudopyramidatum Lund. III. Th. YII. S. 
14. G. variolatum Lund. III. Th. IY. N. 
*15. G. ocellatum B. Eichl. & Gutw. (in Rospr. Akad. Umiej. 
Krakow. Wydz. matem.-prz., ser. ii. tom. viii. vol. xxviii. (1895) 
p. 164, t. iv. f. 7. 
Yar. incrassatum var. n. (PI. YI. fig. 12.) 
Yar. sinu semper aperto; semicellulis apicibus sub- 
truncatis, in centro incrassatis et luteo-fuscis, cum 
scrobiculis parvis 3-6 ; a latere visis circularibus ; a 
vertice visis ellipticis, incrassatis, et leviter tumidis, 
ad medium utrobique. 
Long. 28-30 y ; lat. 24-26 y ; lat. isthm. 5 * 5-6 * 5 y ; 
crass. 14*5-15 y. IH. Th. YI. N. 
The thickened area in the centre of the semi-cells is always more 
or less coloured, and possesses a central larger scrobiculation surrounded 
by a variable number of somewhat smaller ones. 
16. G. nitidulum De Not. III. Th. 
17. G. subtumidum Nordst. III. Dj. IY. Ks. YIII. H. 
*18. G. Klebsii Gutw. YI. N. 
