FRESHWATER ALGÆ FROM TUDDAL IN TELEMARK. 177 



175. Cosmarium Blyttii. Wille. 



General, and often in abundance. Size: long. 17,5 ^t, lat. 15 ju. 



175 a. var. Novœ-Sylvœ. W. & G. S. West. 



Rare. 



176. Cosmarium subcrenatum. Hantzsch. • 

 Frequent, and in abundance. 



177. Cosmarium suhprotumidum. Nordst. 

 Somewhat rare. 



178. Cosmarium calcareum. Wittr. 



Very rare, only in a single sample. Size: long. 23 (.c, 

 lat. 20 f.1, lat. isthm. 6,5 fi. 



179. Cosmarium subcostatum. Nordst. 

 Scarce. 



180. Cosmarium costatum. Nordst. 

 Scarce. 



181. Cosmarium binum. Nordst. 

 Very rare. 



182. Cosmarium speciosum. Lund. 

 General, but scarce. 



183. Cosmarium subspeciosum. Nordst. 

 Rare, only in a few samples 



184. Cosmarium tetraophtalmum. Breb. 



General, but scarce. Size: long. 105 & 75 /n, lat. 80 & 50 fx, 

 lat. isthm. 28,5 & 20 f^i. The latter was a very small form, 

 but quite typical. 



185. Cosmarium Botrytis. Menegh. 



Far from common. Never from cold water. 



186. Cosmarium ochtodes. Nordst. 



Rare, only in a single sample from 4100 feet. 



187. Cosmarium margaritatum. (Lund.) Roy & Biss. 

 Not uncommon. Size of a small form: long. 60 ^u, lat. 48 /tt, 



lat. islhm. 18 ^i. 



Nyt Mag. f. Naturv. LVII. 19 19. 12 



