196 BTUTTSH DESMTDIACE^. 



Length 42 p, ; breadth 33 ^ ; breadth of isthmus 

 IG/i; thickness 17-18 JJL. 



ENGLAND.- -Bowness, Westmoreland ! Cullingworth, 

 W. Yorks ! Mickle Fell, N. Yorks ! 



WALES.- -Bettws-y-coed !, Capel Curig ! (Coolie $ 

 Wills), Snowdon (Roy), and Yr Orsedd !, Carnarvon- 

 shire. 



SCOTLAND. Orkneys!, Sutherland, Ross, Inverness, 

 Aberdeen, Kincardine, Forfar, Perth, Argyll, Arran 

 (Roy $ Bissett). 



IRELAND.- -Adrigole, Kerry ! 



Geogr. Distribution.- -Norway. Poland. Siam. Cen- 

 tral China. United States. 



This species stands very near to C. nitidulum De Not., but 

 differs in the form of the semicells, which are wider at the 

 apex, and in the presence of two pyrenoids in each chloro- 

 plast. From C. galeritum Nordst. it is distinguished by its 

 smaller size and by its less pyramidate semicells with broader 

 apices. 



Var. validum nob. (PL LXIII, figs. 27-30.) 



C. pachydermum Lund. var. minus Nordst. Norges. Desm. 1873, p. IS, t. 1, 

 f . 7 ; De Toni, Syll. Alg. 1889, p. 970 ; Roy & Biss. Scott. Desm. 1894, 

 p. 170 ; West & G. S. West, Desm. Singapore, 1897, p. 164 ; Fresh w. 

 Alg. Ceylon, 1902, p. 162. 



Cells larger than in the type, with the basal angles 

 sometimes more rectangular (not so rounded) ; cell- 

 wall very firm and punctate. 



Length 56-78 p. ; breadth 46-59 p. ; breadth of isth- 

 mus 17-25 //,; thickness 28 33 /A. 



ENGLAND.- -Near Bowness, Westmoreland (Bissett). 

 Cautley Spout, W. Yorks ! 



WALES. Capel Curig, Carnarvonshire ! 



SCOTLAND.- -Poolewe, Ross ; near Brin, Inverness ; 

 Glen Callater, Aberdeen ; Canlochan, Forfar ; Bannock, 

 Perth; Alva Glen, Stirling (Roy fy Bissett). 



Geocjr. Distribution.- -Norway. India. Ceylon. 

 Singapore. Azores. W. Africa. 



This variety only differs from typical C. pseudonitidulum in 

 its larger size and sometimes in its more rectangular basal 



