486 
Transactions of the Society. 
19. G. Phaseolus Breb. II. Wh. III. Bi., Dj., E., Fg., Mp., 
Th. VII. S. VIII. G., T. 
Forma minor. 
Long. 21 fji ; lat. 18 /x ; lat. isfcbm. 5*5 ll ; crass. 10 /x ; 
VII. Grp. 
20. G. fontigenum Nordst. III. Pu. 
Long. 22 fi ; lat. 25 /x ; lat. isthm. 6 /x ; crass. 11*5 /x. 
21. C. tetrachondrum Lund. III. Mp. 
22. C. Scenedesmus Help. I. Ep. III. Th. 
23. G. pseudoprotnberans Kirchn. I. Ep. III. Th. (with zygo- 
spores). VI. N. 
24. G. rectangulare Grun. III. C., Dj., E. 
25. G. inconspicuum West & G. S. West. III. M. (with zygo- 
spores). 
26. G. bioculatum Breb. II. U. III. Bi., E., Ew., Mp., Pu. 
(with zygospores), Th., Wi. VIII. W. 
Diam. zygosp. s. spin. 17-19 /x; c. spin. 26-28 /x. (PI. 
VI. fig. 17.) 
Var. depressmn Schaar. I. Ep. IV. Ks. 
Var. hians var. n. (PI. VI. fig. 24.) 
Var. sinu apertiori extrorsum, marginibus inferioribus 
semicellularum conyexis, apicibus rectis vel levissime 
retusis ; membrana distincte punctata. 
Long. 17-19 /x; lat. 15-18 /x ; lat. isthm. 3*5-4 pu ; 
crass. 7 *5-8 *5 /x. III. Pu., Th. 
This comes nearest to G. bioculatum var. excavation Gutw., but 
is proportionately shorter ; the apex of the sinus is subacute ; the 
apices of the cells are straight or very slightly retuse; and the 
membrane is punctate. 
*27. G. aspherosporum Nordst., var. strigosum Nordst. III. Pu. 
Long. 10*5-11 /x ; lat. 9*5 /x; lat. isthm. 3*5 /x; crass. 
5 /x. 
28. G. tinctum Balfs. I. Ep. III. Di., E., Ew., Pu., Th., Wi. 
IV. Ks. VI. N. VII. D., Gp. VIII. G., H, T. 
29. G. succisum West. III. Pu. 
30. G. abbreviation Bacib. I. Ep. II. U. 
31. G. pygmseim Arch. III. Mp. 
32. G. truncatellum Perty. III. C. 
Long. 9 * 5-10 * 5 ya ; lat. 12 * 5-14 * 5 /x ; lat. isthm. 5 * 5 /x ; 
crass. 5 /x. (PI. VII. fig. 3.) 
*33. C. geometricum West & G. S. West. III. Pu. 
*34. G. hexangulare Nordst. III. Th. 
*35. G. Heimerlii West & G. S. West. (G. minutissimum Hei- 
merl non Arch.) III. Mp., Th. IV. Ks. 
36. C. sphagnicolum: sp. n. (PI. VI. figs. 13, 14.) 
C. minutissimum, paullo latius quam longum, modice con- 
