60 BRITISH DESMIDIACEJ-]. 



Cells oblong-cylindrical, 1 ^2 times longer than their 

 diameter, apices broadly rounded ; chloroplast similar 

 to that of the preceding species. 



Zygospore globose or rarely subquadrangular. 



Length 22-46 fi ; breadth 18-24 f< ; diam. zyposp. 

 25-30 p. 



ENGLAND. Cumberland ! Westmoreland ! Yorks ! 

 Lancashire! Cheshire (//o//). Leicester (J!o//). Essex! 

 Surrey! Hants I (Bennett). Cornwall! 



WALES. Fairly general in Carnarvonshire ; up to 

 2,700 ft. on Glyder Fawr ! 



SCOTLAND. General ! (fivi/ <$ 7>/x.sv/f). Harris and 

 Lewis, Outer Hebrides ! Orkneys ! Shetland s ! 



IRELAND. Galway ! Kerry ! Dublin and Wicklow 

 (Archer). Donegal! Londonderry! Down! 



Gcoi/r. Distribution. -France. Germany. Austria. 

 Portugal. Sweden. Norway. Singapore. Mada- 

 gascar. New Zealand. West Africa. United States. 



o. Cylindrocystis obesa West & G. S. West. 

 (PI. V, fig. 8.) 



Cylindrocystis obesa West & G. S. West, Alg. N. Ireland, 1902, p. 20, t. 2, 

 f. 6. 



Cells of medium size, about If times longer than 

 their diameter, rhomboid-ellipsoid with the apices 

 broadly rounded, unconstricted ; cell- wall smooth and 

 colourless ; chloroplasts stellate with numerous radiat- 

 ing processes, pyrenoids very large; with a distinct 

 vacuole near each apex. 



Zygospore unknown. 



Length 48 p ; breadth 27 /u. 



IRELAND. Near Gweedore, Co. Donegal ! 



This species bears considerable resemblance to C. pyramidal a 

 West & G. S. West, a plant only known from Ceylon, but is 

 distinguished by its relatively greater width, the more rounded 

 :i piers, and the absence of a constriction. (Consult West & 

 G. S. West, Freshw. Alg. Ceylon, p. 134, t. 18, f. 1, 2). 



