STAURASTRUM. 75 



with about 18-20 granules, the apical ones more or less 

 flattened or emarginate, granules in front view of semi- 

 cell arranged in about 7 longitudinal rows, the median 

 row incomplete, and the uppermost granule of each row 

 larger and emarginate. Vertical view 3-5-angular, sides 

 straight and granulate, angles broadlv rounded and 



/ 



bearing a few spines longer than the rest, with a curved 

 series of about 6 emarginate granules within each lateral 

 margin ; centre of apex smooth. 



Zygospore orbicular, spines twice branched at the 

 apex. 



Length 42-52 u ; breadth 34-47 <j. ; breadth of isth- 

 mus 12-1 5 p ; diam. zygosp.. without processes, 47'5[JL ; 

 with processes, 75 u. 



ENGLAND.- Westmoreland! (Bissett). N. and K. 

 Yorks! Lancashire! Leicester (Roy). Warwicks (Witts). 

 Gloucester (Ralfs). Surrey ! Sussex (Ralfs). Hants ! 

 Devon (Harris) ! Cornwall ! 



WALES. Capel Curig and Llyn Tdwal, Carnarvon- 

 shire ! Ffestiniog, Merioneth ! 



SCOTLAND. Sutherland, Ross, Aberdeen, Kincardine, 

 Forfar. Perth and Fife (Roy & Biss.). Loch Shiel, 

 Inverness ! Orkneys ! In the plankton ! 



IRELAND. Clare Island, Mayo ! Xear Oughterard and 

 Ballynahinch. Co. Galway ! CarrantuohilL Co. Kerry 

 Dublin and Wicklow (Arch.). Munster, Leinster and 

 Connaught (Adams). 



Geogr. Distribution.- -France. Germany. Gahcia and 

 Austria. Sicilv. Sweden. Faeroes. United States. 



*/ 



96. Staurastrum maamense Arch. 

 (PL CXXXIX, fig. 10.) 



St. maamense Arch, in Quart. Journ. Micr. Sci. vol. I'. 18(jJ. P.*'": ^oke, 

 Brit. Desm. 1887, p. 155, t. 53, f . 3 ; De Tom, Syll. ; l175 ' 



West, Alg. W. Ireland, 1892, p. 176 ; Roy & >- ; ;./ ; 



p. 184 ; West & G. 8. West, Some X. Amer. Desm. 

 Freshw. Phytoplankton, 1909, p. 202. ,, , 



St. pseudocrenatum Lund. Desm. Suec. 1871, p. bo, t. 

 Alg. U. S. 1887, p. 42, t. 57, f. 9, 10. 



