184 BEITISH DESMIDIACE^E. 



WALES. Capel Curig (Roy) and Glyder Fawr ! Car- 

 narvonshire. 



SCOTLAND.- -Loch Luichart, Ross (N. C.). 



IRELAND. Carrantuohill, Kerry ! Dublin and Wick- 

 low (Arch.}. Clare Island, Mayo ! 



Geogr. Distribution. France. Germany. Austria. 

 Servia. Norway. Sweden. Denmark. Bornholm. 

 Finland. N. Russia. Greenland. Siberia (var.). Japan. 

 United States. 



Typical St. monticulosum is not a common Desmid in the 

 British Isles, var. bifarium Nordst. being much more frequently 

 found. Apparently W. & G. S. West did not thoroughly under- 

 stand this species, for PL CLIV, fig. 11 is a drawing showing 

 their idea of the typical form. This obviously does not belong 

 to St. monticulosum, however, and the localities for the species 

 with the Wests' authority (shown !) should consequently not be 

 taken as correct. PL CLIV, fig. 8 is a drawing by the present 

 writer from L. Luichart, and it agrees exactly with a drawing of 

 Gronblad (Act. Soc. Flor. Fauna Fenn.' 47, 1920, p. 90), who 

 has recently examined de Brebisson's original specimens, and 

 gives a good review of the species and its various varieties. 



Var. bifarium Nordst. (PI. CLIV, fig. 9.) 



St. monticulosum var. /3 bifarium Nordst. Norges Desm. 1873, p. 31, t. 1, 



f. 14 ; Wolle, Desm. U. S. 1884, p. 144, t. 51, f. 24-26 ; De Toni, Syll. Alg. 



1889, p. 1157 ; West & G. S. West, Alg. Madag. 1895, p. 73, t. 8, f. 21 ; 



Borge, Botan. Notiser, 1913, p. 50; Gronblad, Desm. Keuru, 1920, p. 89. 

 St. senarium v. alpinum f. tatrica Racib. Norm. Desni. Polon. 1885, p. 32, 



t. 12, f. 7. 

 St. senarium var. bifarium Kaiser, Alg. Traunst. 1914, p. 153. 



Semicells with the apical processes emarginate at the 

 apex, and with an additional series of similar bifid 

 prominences round the middle part of the semicell, two 

 between each pair of angles. 



Length, without processes, 29-37 (JL ; breadth, without 

 processes, 30-34 (JL ; breadth of isthmus 10-13(ji. 



SCOTLAND. Falls of Connon, Ross ; near Ballater, 

 Aberdeen (Roy & Biss.). Plankton of Loch Diracleet, 

 Harris, Outer Hebrides ! 



Geogr. Distribution. Germany. Norway. Sweden. 

 Finland. Poland. Madagascar. Australia. United States. 



