170 BRITISH DESMIDIACEJ1. 



161. Cosmarium solidum Nordst. 

 (PI. LXXX, fig. 23.) 



Cosmarium punctulatum Nordst. Desm. Spetsb. 1872, p. 26, t. 6, f . 1; et 



(3 triquetrum Nordst. 1. c. f. 2 [not C. punctulatum Breb. 1856]. 

 C. solidum Nordst. in Botan. Notiser, 1887, p. 160 ; Freshw. Alg. N. Zeal. 



1888, p. 48 ; Holdt, Desm. Gronland, 1888, p. 27 ; De Toni, Syll. Alg. 



1889, p. 965 ; Nordst. Index Desm. 1896, p. 235 ; West & GK S. West, 

 Alga-fl. Yorks. 1900, p. 72. 



? C. crenatum Ralf s forma a Gntw. Flor. Glon. Okolic Lwowa, 1891, p. 41, 



t, 1, f. 12. 

 Ursinella solida Kuntze, Revis. gen. plant. 1891, p. 925. 



Cells small, rather longer tlian broad or up to 1^- 

 times as long as broad, moderately deeply constricted, 

 sinus linear ; semicells subrectangular, basal angles 

 obtuse, apical angles obtusely rounded, apex truncate 

 and slightly 4-crenate-undulate, sides slightly convex 

 and 57-crenate-undulate. Side view of semicell ovate- 

 truncate, with a delicately undulate apex. Vertical 

 view broadly elliptic, with the sides and poles slightly 

 undulate. Cell-wall granulate, granules small and 

 disposed in more or less regular vertical series. 



Zygospore unknown. 



Length 22-35 M ; breadth 21-28 jt ; breadth of isth- 

 mus 1 0-1 2 ,u ; thickness 16-19 '2 /n. 



ENGLAND. --Cronkley Fell and Carltoii Bank, N. 

 Yorks ! 



Geogr. Distribution.- -Germany. Greenland. Spitz- 

 bergeii. Nova Zembla. 



This species is distinguished from C. punctulatum Breb. by 

 the form of its semicells and the different nature of its granu- 

 lation. 



162. Cosmarium Etchachanense Roy & Biss. 



(PI. LXXXI, fig. 1.) 



Cosmarium Etchachanense Roy & Biss. Scott. Desm. 1894, p. 101, t. 1, 

 f. 15 ; Nordst. Index Desm. 1896, p. 119; West & GK S. West, Alga-fl. 

 Yorks. 1900, p. 72 ; Notes Alg. Ill, 1903, p. 75. 



Cells small, about 1J times as long as broad, deeply 

 constricted, sinus narrowly linear ; semicells semi- 

 circular-elliptic, basal angles obtuse, sides convex 

 and 6-7-undulate-crenate, apex subtruncate and very 



