2 BRITISH DESMIDIACE^E. 



ENGLAND.- -Helvellyn, Westmoreland ! Not un- 

 common on wet rocks, W. and N. Yorks ! Enbridge 

 Lake, Hants. (Roy). Near the Lizard, Cornwall! 



AVALES. Capel Cnrig (Oooke fy Wills), and Grlyder 

 Fawr, Carnarvonshire ! 



SCOTLAND.- -Ross, Inverness, Aberdeen!, Kincardine, 

 Forfar !, Perth!, Stirling, Arran (Roy Sis sett). 

 Shetlands ! 



IRELAND.- -Near Onghterard, Galway ! Glen Caragh, 

 Kerry ! 



Geogr. Distribution.- -France. Germany. Galicia. 

 Bohemia. Poland. Italy. Norway. Sweden. Born- 

 holm. Bosnia. Greenland. Spitzbergen. Nova 

 Zembla. Ceylon. New Zealand. Sandwich Islands. 

 United States. Ecuador. Argentina. 



C. Holmiense is mostly an alpine and arctic species, gene- 

 rally occurring among mosses and various algge on wet rocks, 

 although it also occurs in some of the bogs and boggy rills 

 high up on the mountains. It is usually found associated 

 with C. anceps Lund., C. galeritum Nordst., C. speciosum 

 Lund., C. ochthodes Nordst., and other species which have a 

 preference for great aeration. 



It is a characteristic species, being readily recognized by 

 the dilated apex and the irregular undulation of the upper 

 parts of the lateral margins of the semicell. In size it is very 

 variable ; the largest recorded specimen is one mentioned by 

 Nordstedt (' Desm. Arctoas,' 1875, p. 18) as " forma maxima ' 

 (length 98 [j. ; breadth 51 ju; breadth of apex 36 /LL ; breadth 

 of isthmus 27 /i). From the Tyrol the same author has 

 described a trigonal variety, in which the vertical view is 

 trigonal with straight sides and rounded angles (vide C. 

 Holmiense var. trigonum ' Nordst. Desm. Ital/ 1876, p. 31, 

 t. 12, f. 6). 



Var. integrum Lund. (PL LXV, figs. 3-5.) 



C. Holmiense Lund. var. integrum Lund. Desm. Suec. 1871, p. 49 ; Nordst. 

 Desm. Spetsb. 1873, p. 28, t, 6, f. 5 ; Hansg. Prodr. Algenfl. Bohm. 

 1888, p. 197 ; Boldt, Desmid. Gronland, 1888. p. 11 ; Borge, Subfoss. sotv. 

 alg. Gotl. 1892, p. 57, t. 1, f. 10 ; West, Alg. Engl. Lake Distr. 1892, 

 p. 724 ; Eoy & Hiss. Scott. Desm. 1894, p. 103 ; Nordst. Index Desmid. 

 1896, p. 140; West & GK S. West, Some Desm. U.S. 1898, p. 300; 

 Alga-fl. Yorks. 1900, p. 80 ; Alg. N. Ireland, 1902, p. 32. 



