CLOSTERIUM. 113 



Section A. 



1. Closterium Cynthia De Not. 

 (PL XI, figs. 1-3.) 



Closterium Cynthia De Not. Dcsm. Ital. 1867, p. 65, t. 7, f. 71 ; Lund. 



Desm. Suec. 1871, p. 78; Cooke, Brit. Desm. 1886, p. 26, t. Hi, f. 1'; 



West, Alg. N. Wales, 1890, p. 285 ; Alg. W. Ireland, 1892, p. 123 ; 



Roy & Biss. Scott. Desm. 1894, p. 244 ; West & G. S. West, Some N. 



Ainev. Desm. 1896, p. 237 ; Nordst. Index Desm. 1896, p. 96 ; West A 



G. S. West, Alg. S. England, 1897, p. 481 ; Alga-fl. Yorks. 1900, p. 51 ; 



Alg. N. Ireland, 1902, p. 24 ; Freshw. Alg. Ceylon, 1902, p. 140. 

 Closterium Archer ianum c. Cynthia Klebs, Desm. Ostpreuss. 1879, p. 13, 



t. 1, f. 12, a et c. 

 Arthrndia Cynthia Kuntze, Revis. gen. plant. 1891, p. 883. 



Cells small, about 6-10 times longer than their 

 diameter, strongly curved, outer margin 120 140 

 (rarely 1 70) of arc, inner margin not tumid, gradually 

 narrowed to the apices, which are obtusely rounded ; 

 pyrenoids 36 in each chloroplast ; terminal vacuoles 

 generally with one moving granule ; cell- wall finely 

 striate, about 14 stria? visible across the cell, pale 

 yellow or yellow-brown in colour. 



Zygospore globose and smooth. 



Distance between apices 73-1 GO//,; breadth 11-18//,; 

 diam. of zygosp. 28-31 /a. 



ENGLAND. Westmoreland! (Bissett). N. Yorks! 

 Lancashire! Surrey! Hants! Cornwall! (Marguand). 



WALKS. Capel Curig! (Cooke fy TFi/Zs),.Pen-y-gwryd 

 (-Bo?/), Llyn Padarn ! , Llyn Idwal ! , and near Con way, 

 Carnarvonshire ! 



SCOTLAND. Sutherland ! , Ross, Inverness ! , Nairn, 

 Aberdeen ! , Kincardine, Forfar ! , Perth ! , Dumbarton 

 (Roi/ cj- ///N.vr//). Orkneys (Roy cj- Jli^rtt). 



IRELAND. Clalway ! Mayo ! Kerry ! Donegal ! 

 Dublin and Wicklow (AirJier). 



Geo</r. Distribution. France. Austria. Hungary. 

 Italy. Norway. Sweden. Denmark. India. Ceylon. 

 Sumatra. New Zealand. Australia. East Africa. 

 United States. Brazil. 



This is a very well-marked species which could only he 

 confused with 01. Jenntri, ('!. parvuhim,or 01. TV>/?/.v. From 

 all these species it differs in the single corpuscle present in 



8 



