162 BRITISH DESMIDIACE^E. 



Woodbury Common (4-radiate), Devon ! (Harris). 

 Withiel, Cornwall ! 



WALES. Capel Curig ! (Cooke & Wills), Llyn Padarn ! 

 and Pen-y-gwryd (Roy), Carnarvonshire. In the plank- 

 ton ! 



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

 Forfar and Perth (Roy & Biss.). 



IRELAND. --Near Glenties and Lough Gartan, Donegal! 

 Clare Island, Mayo ! Ballynahinch, Galway ! Carrantuo- 

 hill, Kerry ! Castletown, Cork ! Dublin and Wicklow 

 (Arch.). 



Geogr. Distribution.- -France. Germany. Switzerland. 

 Galicia and Austria. Hungary. Servia. Italy. Norway. 

 Sweden, Denmark. Finland. N. Russia. Nova Zembla. 

 Greenland. Siberia. Japan. Burma. Australia. New 

 Zealand. United States. Patagonia. Antarctic. 



The distinctive feature of St. aculeatum is the possession of 

 two series of spines stretching from angle to angle of the cell, a 

 dorsal series on the apex, and a lateral series lower down. The 

 median spines of the dorsal series are frequently emarginate, 

 and some of the spines of the lateral series may occasionally be 

 duplicated, or very much reduced in size, but the two series can 

 always be recognised. 



153. St aura strum contr over sum Breb. 

 (PL CLIV, figs. 1-4.) 



Stow/rostrum controversum Breb. in Menegh. Synops. Desrn. 1840, p. 228 ; 



Ralfs, Brit. Desm. 1848, p. 141, t. 23, f. 3 ; Arch, in Pritch. Inf. 1861. 



p. 742 ; De Not. Desm. Ital. 1867, p. 49, t. 4, f. 39 ; Wolle, Desm. U. S. 



1884, p. 143, t. 45, f. 24, 25 ; Cooke, Brit. Desm. 1887, p. 173, t. 60, 



f. 1 ; De Toni, Syll. Alg. 1889, p. 1216 ; West, Alg. N. Wales, 1890, 



p. 19, f. 22 ; Alg. W. Ireland, 1892, p. 184 ; Roy & Biss. Scott. Desm. 



1893, p. 18 ; Schmidle, Beitr. Algenfl. Rheineb. u. Schwarzwald. 1895, 



p. 82, t. 1, f. 22 ; West & G. S. West, Alg. S. England, 1897, p. 496 ; 



Liitkem. Desm. Millstiittersees, 1900, p. 20, t. 1, f. 49 ; Comere, Desm. 



de France, 1901, p. 151, t. 11, f. 13 ; West & G. S. West, Alga-fl. Yorks. 



1902, p. 106. 



St. aculeatum Ralfs, in Ann. Mag. Nat. Hist. vol. 15, 1845, p. 156, t. 11, f. 13. 

 St. aculeatum var. controversum Rabenh. Flor. Europ. Alg. 1868, p. 217 ; 



Jacobs. Desm. Danem. 1875, p. 207. 



Cells usually under medium size, about as long as 

 broad, or up to 1| times broader than long, deeply con- 



