203 



This variety differs from C. pyramidatum var. angustabum 

 in the more rectangular basal angles of the semicells and the 

 more protracted apices, as well as in the single pyrenoids. 



A small form of it is known from Australia and the West 

 Indies: length 35-36*5^; breadth 22-24 n ; breadth of 

 isthmus 6*5-12 u thickness 



50. Cosmarium variolatum Lund. 

 (PL LXIV, figs. 14-16.) 



Cosmarium variolatum Lund. Desm. Suec. 1871, p. 41, t. 2, f. 19 ; Wolle, 

 Desni. U. S. 1884, p. 63, t. 16, f . 3, 4 ; Cooke, Brit. Desm. 1886, p. 84, 

 t. 36, f . 10 [figure bad] ; De Toni, Syll. Alg. 1889, p. 954 ; West, Alg. W. 

 Ireland, 1892, p. 144 ; Alg. Eng. Lake Distr. 1892, p. 724 ; Eoy & Biss. 

 Scott. Desm. 1894, p. 177 ; Nordst. Index Desni. 1896, p. 267 ; West & 

 G. S. West, Welw. Afric. FresliAv. Alg. 1897, p. 115 ; Alg. S. England, 

 1897, p. 485 ; Alga-fl. Yorks. 1900, p. 78 ; Alg. N. Ireland, 1902, p. 33. 



C. pseudopyramidatum Lund. var. variolatum Hansg. Prodr. Algenfl. 

 Bohm. 1888, p. 198. 



Ursinella variolata Kuntze, Revis. gen. plant. 1891, p. 926. 



Cells small, about If times longer than broad, deeply 

 constricted, sinus narrowly linear witli a slightly-dilated 

 apex ; semicells semi-elliptic, basal angles very slightly 

 rounded, sides convex and upwardly converging, apex 

 very narrow, truncate, and often subretuse. Side view 

 of semicell obovate-elliptic. Vertical view broadly 

 elliptic, ratio of axes about 1 : 1'S. Cell- wall firm, 

 densely scrobiculate, the scrobiculations being rela- 

 tively large and very conspicuous. Chloroplasts axile, 

 each with one pyrenoid. 



Zygospore unknown. 



Length 32-35 /x; breadth 18-21 p.; breadth of isth- 

 mus 5-6'5/>t; thickness 15-16*5 //,. 



ENGLAND. Near Bowness, Westmoreland (Bissett). 

 Baildon, W. Yorks ! Thursley Common, Surrey ! New 

 Forest, Hants ! 



WALES. Capel Curig, Carnarvonshire ! (Cooke ~ 

 Wills). 



SCOTLAND. Ross, Aberdeen, Kincardine, Perth, 

 Argyll, Arran (Roy fy Bissett). Sutherland ! Outer 

 Hebrides ! Orkneys ! 



IRELAND. E. of Grlenties, Donegal ! Ballynahinch, 



