— 166 — 



35. C. reguläre Bréb. in Mém. Soc. Sciences, Cherbourg, 1856, IV, 

 p. 304, t. II, f. 35. 



Forma apicibus crassioribus ; striis validis, visis 1 1 . 

 Long. 240//; lat. 26,5//.; lat. apic. 8,5 p. 



With the preceding species. 



Area: Europe, W.Africa, India, Australia. 



36. €. Ralfsii Bréb. in Ralfs Brit. Desm. 1848, p. 174, t. XXX, f. 2. 



Var. hybridum Rabenh. Krypt. Fl. Sachs, p. 174; Flor. Europ. Algar. 

 HI, p. 135. 



Long. 464 p • lat. 29,5 p ; lat. apic. 6 p. 

 Area: Europe, Ceylon and Singapore. 



37. C. Kützingii Bréb. in Mém. Soc. Sciences, Cherbourg, 1856, IV, 

 p. 156, t. II, f. 40. 



Long. 467 — 540//; lat 17/;. 



In stagnant water among Spirogyra decimina var. 



Area: Europe, N.America, Madagascar, India, Ceylon, Japan, New Zealand 

 and Australia. 



38. €. Cornu Ehrenb. 1830; Ralfs Brit. Desm. 1848, p. 176, t. XXX, 

 f. 6 f et g. 



Var. siamense West & G.S.West, n. var. (Tab. nostr. II, fig. 6 — 7). 



Var. cellulis minus curvatis; zygospora subquadrata, angulis 

 submamillatis. 



Long. 140- 165//; lat. 5,5— 7,5 // ; diani. zygosp. 23—25//. 



This variety differs from typical Cl. Cornu Ehrenb. in being somewhat 

 less curved, and in the form of the zygospore, the angles of which are 

 not so produced and do not project within the empty semicells. The 

 zygospore is surrounded by a mucous investment and the semicells are 

 attached to the outer edge of this mucus. 



In muddy ricefields. 



Area: Europe, N. and S.America. Australia. 



39. C. tu mid il m Johnson in Bull. Torr. Botan. Club, vol. 22, no. 7, 

 July 1895, p. 291, t. 293, f. 4. C. Cornu var. ß Ralfs Brit. Desm. 1848, 

 p. 176, t. XXX, f. 6 a—e. C. Cornu et forma major Wille in Öfvers. af 

 K. Vet.-Akad. Förh. 1879, no. 5, p. 59, t. XIV, f. 80, 81. 



a. Forma cellulis crassioribus. (Tab. nostr. II, fig. 4). 

 Long. 125//; lat. 18,5//; lat. apic. 4 p.. 



The form observed was proportionately a little thicker than CI. tumidum 

 Johns., and the ventral margin was slightly less tumid. The relative in- 

 crease in thickness was due to the somewhat greater curvature of the 

 dorsal margin. The cell-wall was quite smooth and colourless and the 

 apices were truncate exactly as in Johnson's figures. 



