138 BRITISH DESMIDIACEJE. 



gent) series of granules, 6 or 7 in each series, and 

 gradually becoming reduced in size from the base 

 upwards. Side view of semicell oblong-rectangular, 

 slightly tumid at the base on each side, apex sub- 

 truncate. Vertical view elliptic with a slight central 

 inflation. 



Zygospore unknown. 



Length 55-58 JJL ; breadth 4550 p. ; breadth of 

 isthmus 12jut; thickness 23 p,. 



IRELAND. --Creggan Lough, Galway ! 



Geogr. Distribution. United States. 



This species should be compared with some forms of 

 C. Botrytis, from which it is distinguished by its slightly 

 smaller size and the different granulation. 



141. Cosmarium intermedium Delp. 

 (PI. LXXVI, fig. 10.) 



Cosmarium intermedium Delp. Desm. subalp. 1877, p. 25, t. 8, f. 7-10 ; 



De Toni, Syll. Alg. 1889, p. 996; Roy & Biss. Scott. Desm. 1894, p. 104 ; 



Nordst. Index Desm. 1896, p. 148. 

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



Cells of medium size, about 1J times as long as 

 broad, deeply constricted, sinus narrowly linear with 

 a dilated extremity ; semicells somewhat pyramidate- 

 semicircular with a broadly rounded apex, basal 

 angles rounded. Side view of semicell angular-ovate, 

 lower parts of sides upwardly divergent, upper parts 

 convergent, apex rounded. Vertical view elliptic, 

 ratio of axes 1:2. Cell- wall uniformly granulate; 

 granules rounded, arranged in concentric series. 

 Chloroplasts axile (?), with two pyrenoids. 



Zygospore unknown. 



Length 79 p. ; breadth 61 JJL ; breadth of isthmus 

 19 ju, ; thickness 28 JJL. 



SCOTLAND.- -Near Portree in Skye, Inverness ; near 

 Aboyne, Aberdeen ; near Tobermory in Mull, Argyll 

 (Roy fy Bissett). 



Geogr. Distribution. Germany (form). Italy. 

 United States (?). 



