COSMAEIUJI. 143 



of marginal verrucas. In some parts of Sutherland and the 

 Outer Hebrides it is quite common. 



The smallest recorded form (forma minor) is from Ceylon : 

 length 34-5-37 M ; breadth 23-26 ,.* (vide W. & G. S. West, 

 'Freshw. Alg. Ceylon/ 1902, p. 171). 



Forma hexasticha (Lund.) Nordst. (PI. LXXVII, 



fig. 4.) 



Cosmarium hexastichum Lund. Desni. Snec. 1871, p. 33, t. 3, f. 13 ; Nordst. 

 Norges Desm. 1873, p. 14; Nordst. Desm. Gronl. 1885, p. 9; Cooke, 

 Brit. Desm. 1887, p. 115, t. 40, f . 9 ; De Toni, Syll. Alg. 1889, p. 1023; 

 Eoy & Biss. Scott. Desm. 1894, p. 103. 



C. quadrifarium forma hexasticha (Lund.) Nordst. Freshw. Alg. N. Zeal. 

 1888, p. 49 ; West, Alg. N. Yorks, 1889, p. 293 ; Alg. W. Ireland, 1892, 

 p. 158 ; Schmidle, Lappmark Siisswasseralgen, 1898, p. 39 ; West & 

 G. S. West, Alga-fl. Yorks. 1900, p. 70; Borge, Alg. erst. Eegnell. 

 Exped. II, Desmid. 1903, p. 100. 



Ursinella hexasticha Kuntze, Eevis. gen. plant. 1891, p. 924. 



Semicells with 6 parallel series of emarginate 

 verrucas in the marginal region, two series usually 

 visible within the marginal warts ; central granules 

 variable, commonly similar to those of the type, but 

 sometimes in 4 transverse series. Poles of side and 

 vertical views with 6 granules. 



Length 40-53^; breadth 32-44 ^ ; breadth of 

 isthmus 14-21 /t ; thickness 21-31^. 



ENGLAND. Mickle Fell, N. Yorks ! 



WALES.- -Capel Curig and Llyn-y-cwm-ffynon, Car- 

 narvonshire ! 



IRELAND.- -Ballynahinch, Galway ! Adrigole, Kerry ! 



Geogr. Distribution.- -Germany. Norway. Sweden. 

 Greenland. Siam. Australia. New Zealand. Brazil 

 (form) . 



In the British Islands this form is much rarer than the one 

 with only four marginal series of truncate-emarginate warts. 



Forma octasticha Nordst. 



C. hexastichum var. octastichum Nordst. Norges. Desm. p. 14; Boldt, 

 Desmid. Gronland. 1888, p. 23 ; Eoy & Biss. Scott. Desm. 1894, p. 103. 



C. quadrifarium forma octasticha Nordst. Freshw. Alg. N. Zeal. 1888, 

 p. 49. 



Semicells with 8 parallel series of emarginate warts 



