COSMARIOl. 7, 



97. Cosmarium pseudobiremum Boldt, 

 (PL LXXI, fig. 35.) 



Cosmarium pseudobiremum Boldt, Siber. Chlorophy. 1885, p. 102, t 5 f <> 

 De Toni, Syll. Alg. 1889, p. 1042; Gutw. Flor. Glon. Okolic Lwowa^ 

 1891, p. 56; Roy & Biss. Scott. Desm. 1894, p. 172; Kordst. Imlcx 

 Desm. 1896, p. 208. 



Ursinella pseudobiremis Kniitze, Revis. gen. plant. 1891, p. 925. 



Cells small, a little broader than long, deeply con- 

 stricted, sinus narrow ; semicells transversely hexa- 

 gonal-elliptic, lateral angles obtuse, superior angles 

 broadly rounded, apex wide and almost straight 

 (faintly convex). Side view of semicell subcircular. 

 Vertical view narrowly elliptic, with a rather broad 

 protuberance at the middle on each side, ratio of axi s 

 about 1:2. Cell- wall smooth. 



Zygospore unknown. 



Length 22-27 //, ; breadth 28-30 ; breadth of isthmus 

 13 p; thickness 12-14 p.. 



SCOTLAND.- -Foot of Birsemore, near Aboyne, Aber- 

 deen (Poy $ Bissett). 



Geoyr. Distriltution.- -Greenland. Siberia. 



This species should he compared with C. albreviatum Kacib., 

 from which it differs in its more rounded semicells,, its broader 

 isthmus, and its tumid vertical view. 



98. Cosmarium bireme Xordst, 

 (PI. LXXI, figs. 36, 37.) 



Cosmarium bireme ISTorclst. Desm. Brasil. 1870, p. 212, t. 3, f. 33 ; Xorges 

 Desm. 1873, p. 18 ; Wolle, Desm. U.S. 1884, p. 82, t. 19, f. 23, 24; Wille, 

 Sydamerik. Alo-fl. 1884, p. 16 ; De Toni, Syll. Alg. 1889, p. 1033 ; Boy .V 

 Biss. Scott, Desm. 1894, p. 42 ; Nbrdst. Index Desm. 1896, p. 62 ; West 

 & G. S. West, Freshw. Alg. Ceylon, 1902, p. 165, t. 20, f. 30. 



Ursinella biremis Kuntze, Eevis. g'eii. plant. 1891, p. 924. 



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

 stricted, sinus very narrow; semicells subellipsoid- 

 hexagonal, basal and lateral angles obtuse, upper 

 anoies broadly rounded, apex truncate and almost 

 straight. Side view of semicell circular, with a lono- 



c*^ ^2 



papilla at the middle on each side. Vertical view 

 elliptic, with a long and somewhat conical papilla at 



