COSMARIUM. 103 



SCOTLAND.- -Loch Ruthven, Inverness ; Slewdrum, 

 Aberdeen ; Xigg, Kincardine ; Bracklin, Perth ; Alva 

 G-len, Stirling (Ron fy Bis sett). New Galloway, Kirk- 

 cudbright ! Orkneys ! Shetlands ! 



IRELAND.- -Donegal ! Gralway ! Kerry! Londonderry! 

 Down ! Armagh ! 



Geogr. Distribution.- -France. Germany. Hungary. 

 Italy. Norway. Sweden. Nova Zembla. Ceylon. 

 Burma. E. Africa (Somaliland). United States. 



This variety is frequent in the British Islands, and the 

 extreme forms scarcely appear to belong to C. Iseve. It is 

 not possible to discriminate between the various forms met 

 with, as the complete range of variation known can be found 

 amongst individuals in the same collection, and the two halves 

 of the same cell may be very different from each other. The 

 variation is principally in the angularity of the semicells and 

 in the character of the superior lateral margins, the latter 

 often exhibiting a marked undulation. 



O 



In a pure collection from Somaliland all intermediate stages 

 between typical C. l&ve and the var. septentrionale were 

 observed. 



Var. cymatium West & G. S. West (PL LXXIII, 



fig. 21.) 



C. leeve Eabenh. var. cymatium West & G. S. West, Freshw. Alg. Orkneys 

 and Shetlands, 1905, p. 23, t. 1, f. 19. 



Basal angles of semicells somewhat less rounded 

 than the average, lateral margins minutely undulate. 



Length 24-27 p; breadth 17-18 /A; breadth of 

 isthmus 4*6-5 p.. 



SCOTLAND.- -Hoy, Orkneys ! 



This variety is at once distinguished by the regular and 

 minute undulation of the lateral margins of the semicells. 



114. Cosmarium monochondrum Xordst. 

 (PI. LXXIII, fig. 26.) 



Cosmarium monochondrum Xordst. Norges Desm. 1873, p. 17, t. 1, f. 6; De 

 Toni, Syll. Alg. 1889, p. 1002; Eoy & Biss. Scott. Desm. 1894, p. 169; 

 Nordst. Index Desm. 1896, p. 175. 



Ursinella monochondra Kuntze, Eevis. gen. plant. 1891, p. 925. 



