COSMARIUM. 175 



Semicells with less distinct marginal grannies ; 

 central scrobiculations absent ; grannies within the 

 lateral margins more numerous. 



Length 37'5/t; breadth 31'5/x,; breadth of isthmus 

 7'5 fj. ; thickness 20 //,. 



SCOTLAND. --Near Kirkwall, Orkneys! 



166. Cosmarium jenisejense Boldt. 

 (PI. LXXXI, fig. 9.) 



Cosmarium jenisejense Boldt,, Siber. Chlorophy. 1885, p. 107, t. 5, f . 13 ; 



De Toni, Syll. Alg. 1889, p. 1049: West, Danish Alga?, 1891, p. 420; 



Eoy & Biss. Scott. Desm. 1894, p. 104; Nordst. Index Desm. 1896, 



p. 150. 

 Ursinella jenisejensis Kuntze, Eevis. gen. plant. 1891, p. 924. 



Cells small, about as long as broad, deeply con- 

 stricted, sinus linear and slightly open outwards ; 

 semicells oblong-elliptic, with the base more flattened 

 than the apex, each lateral margin with about 9 mar- 

 ginal granules, apex truncate and smooth, cell- wall 

 within the margins granulate, the granules in the centre 

 of the semicells being rather more distinct. Side view 

 of semicell circular. Vertical view elliptic, granules 

 arranged in transverse series across the poles, with a 

 small but prominent 3 -granulate tumour at the middle 

 of each side. 



Zygospore unknown. 



Length 3 6 p; breadth 33 7-35 /x, ; breadth of isth- 

 mus 15 p. ; thickness 22*5-23* 5 ft. 



SCOTLAND.- -Cairngorm, Inverness (Roy fy Bissett). 



Geoc/r. Distribution. - Gralicia in Austria (var.). 

 Denmark. Siberia. India. 



C. jenisejense is very closely allied to C. punctulatum and 

 its varieties, amongst which it should perhaps be placed. It 

 differs from C. punctulatum in its more rounded semicells, and 

 in the small but projecting central inflation. We have for 

 the present retained it as a species, as it will be necessary 

 to carefully examine a number of typical specimens in order to 

 discover its true relationships. We are personally acquainted 

 with this species only from the examination of a few half-cells 

 observed in material collected in Denmark. 



