— 162 — 



13. S. gracilis Külz. Spec. Algar. 1849, p. 438; Rabenh. Flor. Europ. 

 Algar. III, p. 237; Petit Spirog. de Paris, 1880, p. 15, t. III, f. 7 — 8. 



Forma cellulis paullo longioribus. 



Grass, cell, veget. 17,5 — 19/7; crass, cell, fruct. 27//; long, zygosp. 

 54 — 63 «; lat. zygosp. 24 — 25//. 



In stagnant water in riverbed. 



Area: Europe and N, America. Abyssinia (var. abyssimca Lagerh.). 



Fam. Desmidiaceæ. 



Gonatozygon De Bary. 



14. G. Ralfsii De Bary Gonj. 1858, p. 76, t. IV, f. 23. 



Long. 163 — 220/7.; lat. 11,6 — 13,5 tx. 



In stagnant water amongst Spiropyra decimina var. 



Area: N. and S. America, W.Indies, Europe, Siberia, China, India, Ceylon, 

 Sumatra, E. and W. Africa, Australia. 



15. C. Kinahani Rabenh. Flor. Europ. Algar. III, 1868, p. 156. 

 Leptocystinema Kinahani Arch. 1858. 



Var. tropicum West & G.S.West, n. var. (Tab. nostr. II, fig. 2). 



Var. cellulis multo crassioribus. 

 Long. 336/y.; lat. 20—23/7. 



In stagnant water, amongst the preceding species. 

 Area of type: Europe. 



Cylindrocystis Menegh. 



16. C. Brébissonii Menegh. 1838; De Bary Gonj. 1858, p. 35, 46, 

 74, t. VII, f. E 1—22. Penium Brêbissonii Ralfs 1848. 



Long. 53 — 78/7; lat. 15 — 16,5/7. 

 In stagnant water in riverbed. 

 Area: Ubiquitous. 



17. €. subpyramidata West & G. S. West , n. sp. (Tab. nostr. II, 

 fig. 8-11). 



G. parva, pæne duplo longior quam lata; cellulis ellipticis, 

 leviter et subgradatim constrictis ad medium ; semicellulis ovato- 

 pyramidatis, polis rotundo-subtruncatis ; membrana glabra achroa; 

 a vertice visis circularibus ; pyrenoidibus singulis, magnis. Zygosporæ 

 nigrescentes, oblongo-rectangulares angulis rotundatis, a latere visse 

 ellipticæ; in medio laterum membrana valde et subirregulariter 

 incrassata. 



Long. 27 — 28 fx; lat. 15 — 16 fx; lat. constrict. 14,5 fx; long, zygosp. 

 32,5—34 n ; lat. zygosp. 23—25 fx ; crass, zygosp. 20 fx. ' 



