EUA STRUM. Gl 



52-57 /x ; length of oblong zygosp. 50-73 //, ; breadth 

 35-40 (JL; length of pap ill re 3-5 '7 /x. 



ENGLAND. Cumberland ! Westmoreland ! (Ralfs). 

 W., N., and E. Yorks (zygospore from Adel Bog, W. 

 Yorks) ! Lancashire! Cheshire (Rolfs). Essex! Surrey 

 (zygospores from Thursley Common) ! Sussex (Rolfs). 

 Kent! Hants! (Rolfs). Wilts! Devon! (Bennett). 

 Cornwall (zygospores from Gumven Moor) ! (Ralfs). 



WALES. Generally distributed and often abundant ! 



SCOTLAND. Very common ! , zygospores from Slew- 

 drum and Albagie, Aberdeen (Roy $ Bis sett). Outer 

 Hebrides (zygospores not uncommon) ! Orkneys ! 

 Shetlands ! 



IRELAND. Common (zygospores from Ballynahinch, 

 Galwav) ! 



e/ / 



Geogr. Distribution. France. Germany. Galicia 

 in Austria. Italy. Xorway. Sweden. Denmark. 

 Bornholm. Finland. Faeroes. Iceland. Greenland. 

 United States. Patagonia (var.). 



E. pectinatum is very widely distributed in all parts of the 

 British Islands,, but the type form is not so abundant as var. 

 inevolutum. The bluntly-conical protuberances of this Euas- 

 trum are very characteristic and are best seen from the vertical 

 view. The angles of the polar lobe and the upper and lower 

 angles of the lateral lobes are bilobulate,, so that in the vertical 

 view there are two conical protuberances at each pole, both of 

 the lower part of the semicell and of the polar lobe. Thus, 

 the outline in vertical view shows ten protuberances in the 

 lower part of the semicell and eight in the polar lobe. 



The zygospores are more frequently met with than those of 

 any other Euastrum. 



i/ 



Var. inevolutum West & G. S. West (PI. XXXIX, 



figs. 13-15.) 



E. pectinatum var. inevolutum West & G. S. West, Freshw. Alg. Ork. and 

 Shetl. 1905, p. 15 (sep.), t. 1, f. 13, 14. 



Cells a little smaller than in the type ; lateral lobes 

 generally more quadrate, outer margins only slightly 

 retuse ; neck of polar lobe relatively broader and 

 shorter ; apex of polar lobe more convex and retuse in 

 the middle, apical angles more rounded ; protuberances 



