STAURASTRUM. 127 



ffynon. Carnarvonshire ! Ffestiniog ! and Dolgelly 

 ( Rolfs ) , Merioneth . 



SCOTLAND. General and variable (Roy & Biss.). 

 Ross ! Inverness ! Aberdeen ! Perth ! Argyle ! Lewis 

 and Harris, Outer Hebrides ! Orkneys and Shetlands ! 

 Rare in the plankton ! 



IRELAXD.- -Donegal ! Mayo and Clare Isle ! Galway ! 

 Kerry ! Dublin and Wicklow (Arch.). Armagh ! 



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

 Galicia and Austria. Hungary. Italy. Servia. Mace- 

 donia. Norwav. Finmark. Sweden. Denmark. Fin- 



u 



land. Poland. X. and S. Russia. Russian Lapland. 

 Faeroes. Xova Zembla. Franz Josef's Land. Spits- 

 bergen. Greenland. Siberia. Mongolia. Japan. Ceylon. 

 Central Africa. United States and Alaska. Canada. 

 West Indies. Patagonia. 



This small and very variable species has an almost world-wide 

 distribution. 



Var. pusillum West. (PL CXLIII, fig. 4.) 



M. /><>lt(nn>fj,/tnn> var. piixilliim \\Vst, Clare Isl. Alg. 1912, p. i'."-. 



Cells much smaller, processes thinner and slightly 

 inflexed ; " body : of semicell similar in form to the 

 type. 



Length 18-1 8 '5 u.. 



IRELAND. Clare Isle, Mayo ! 



Var. subgracile Wittr. 



SV. polymorphum var. subgracile Wittr. Gotl. Ol. sutv. Alg. 1872, p. 51 ; 

 De Toni, Syll. Alg. 1889, p. 1209 ; West, Alg. W. Ireland, 1892, p. 181 ; 

 Liitkera. Desm. Attersees, 1893, p. 567 ; Kaiser, Algenfl. Traunstein u. 

 Chiemgau, I, 1914, p. 153. 



Processes longer than in the type, semicells in vertical 

 view triangular, angles produced, lateral margins con- 

 cave. 



Length 22*5-28 \i ; breadth, including processes, 

 30-45 (j. ; length of processes, 6-12 [i ; breadth of isth- 

 mus 8-9 u.. 



