STAURASTRUM. 7<) 



Dimensions as in the typical form. 



ENGLAND. Dartmoor, Devon (Harris). 



WALES. Capel Curig and Dolbadarn Castle, Carnar- 

 vonshire ! 



Geogr. Distribution.- -Finland. Germany. Switzer- 

 land. Galicia and Austria. Servia. Sweden. Spitz- 

 bergen. Greenland. Sandwich Isles. 



Bennett in 'Freshw. Alg. Engl. Lake Distr.' II, 1888, p. 6, 1. 1, 

 f. 15, 16, has described a var. cumbricum of this species, but 

 his figures and diagnosis are insufficient. It is not impossible 

 that Bennett's variety is identical with the var. perbifidum of 

 West. 



98. Staurastrum echinodermum W. G. S. West. 

 (PI. CXXXIX, figs. 8, 9.) 



*S7. echiHoderniiiHi West & G. 8. West, Notes Al. Ill, 1903, p. 11, t. 44(3, 

 f. 13. 



Cells small, slightly longer than broad, deeply con- 

 stricted, sinus open and acute angled ; semicells angular 

 but roughly elliptical, angles subtruncate, dorsal margin 

 strongly convex, angles and apex with a series of about 

 8, often emarginate, spines, faces of semicell with two 

 transverse series of spines ; vertical view 4- or 5-angular, 

 sides very slightly concave, angles acutely rounded, 

 margins armed with short spines, and with 2 emarginate 

 spines within each lateral margin. 



Zygospore unknown. 



Length, without spines, Sl'Sfi; breadth, without 

 spines, 27 pi ; with spines, 30'8 ji ; breadth of isthmus 

 lO'o fz. 



WALES. Glyder Fawr (at 2700 feet), Carnarvonshire ! 



99. Staurastrum Arnellii Boldt. 

 (PI. CXXXIX, figs. 11-14.) 



Staurastrum Arnellii Boldt, Sibir. Chlorophyc. 1885, p. 112 

 De Toni, Syll. Alg. 1889, p. 1170; West & G. S. West, -Notes 

 1900, p. 297, t, 412, f. 15-18; Alga-fl. Yorks. 1902, p 103 ; Ah 

 Ireland, 1902, p. 51 ; Brit. Freshw. Phytopl. 1 



