50 BRITISH DESMIDIACE.E. 



Cells small, a little longer than broad, subrectangular, 

 only moderately constricted, sinus rather open ; semi- 

 cells transversely subrectangular, sides slightly retuse, 

 apex straight, very slightly concave, or very slightly con- 

 vex, upper and lower angles rectangular but rounded. 

 Side view of cells very slightly constricted, constriction 

 deeper on one side than the other, semicells subquadrate. 

 Vertical view strongly convex on one side and straight 

 or slightly retuse on the other, poles broadly rounded. 

 Cell-wall finely punctate. Chloroplast axile with a 

 central pyrenoid. 



Zygospore unknown. 



Length 14-27 /^ ; breadth 11-24 p.; breadth of 

 isthmus 10-16 p. ; thickness 9'5 15 /x. 



ENGLAND.- -Langdale and Bowness, Westmoreland ! 

 Hawkshead and Risley Bog (.Ro?/), Lancashire ! Culling- 

 worth, Malham Tarn Bo% Penyo'henL Ouefhtershaw 



<-^ ? <J O O 



Tarn (forma m<x/or), and Mossdale Moor, Widdale Fell, 

 W. Yorks ! Mickle, Lands, and Widdale (at 2000 ft.) 

 Fells, Snaizedale Beck and Birkdale Tarn Moss, 

 1ST. Yorks! Subfossil in peat deposit at Filey, E. Yorks ! 

 Chobham Common, Surrey ! 



WALES.- -Siiowdon (above 3000 ft.) !, and Pen-y- 

 g wry d ( Bo ?/) , C arnar von shire . 



SCOTLAND. - -Sutherland !, Ross, Inverness!, Aber- 

 deen, Kincardine, Forfar, Perth !, Argyll, Arran (Roy 

 fy Bissett). Lewis and Harris, Outer Hebrides ! 

 Orkneys ! 



ICELAND. --Creggan Lough and Lakes east of Lough 

 Bofin, Gal way ! Carrantuohill, Kerry ! Dublin and 

 Wicklo w (A i -ell er). 



Geogr. Distribution.- -France. Germany. Austria 

 and Galicia. Hungary. Portugal. Norway. Sweden. 

 Finland. jST. Russia, ^ova Zembla. Xew Zealand. 

 Azores. W. Indies. 



C. obliquumis mostly met with on dripping subalpine rocks, 

 at the margins of peaty pools, and in the peat bogs of upland 

 areas. It does, however, occur in the bogs of heaths and 

 ancient commons, and in the damp climate of Dominica it has 



