rM. 45 



tion, the rounded superior angles of the semicells, and 

 the smooth cell-wall. 



Length 38-45 p; breadth lS'5-22'5 p. ; breadth of 

 isthmus 13*3-16*5 p.; breadth of apex 16*5-18*2 p; 

 thickness 16-17*5 p,. 



Capel Curig !, and Pen-y-gwryd (Hoi/), 



Carnarvonshire. 



SCOTLAND.- -Poolewe, Eoss ; Gright, Vat of Cnlblean 

 and near top of Lochnagar, Aberdeen ; near Cammie, 

 Kincardine ; near Oban, and near Tobermoiy in Mull, 

 Argyll ; Goat Fell and Glen Ranza, Arran (Roy 

 Bissett). 



Geogr. Distribution.- -France. Germany. Sweden. 

 S. Bussia. Kova Zembla. United States. 



This variety, which is mainly distinguished from typical C. 

 decedens by its rounded superior angles, is much more rarely 

 found. It has been customary in the past to regard C. 

 decedens as " var. decedens " of (7. sinuosum, but we think there 

 is every reason for reversing this. The name "decedens" was 

 the first one given to this species and was undoubtedly given 

 to the most distinctive form of it. Moreover, C. decedent 

 is a generally distributed and well-known, alpine and arctic 

 Desrnid, whereas its var. sinuosum ( = C. sinuosum Lund.) is 

 both uncommon and somewhat imperfectly known. 



74. Cosmarium tatricum Eacib. 

 (PI. LXIX, fig. 10.) 



Cosmarium tatricum Eacib. Norm. Desm. Polon. 1885, p. 78, t. 10, f. 12 ; 



De Toni, Syll. Alg. 1889, p. 1035 ; Eoy & Biss. Scott. Desm. 1894, p. 



176 ; Nordst. Index Desm. 1896, p. 250. 

 Ursinella tatrica Kuntze, Eevis. gen. plant. 1891, p. 925. 



Cells of moderate size, about If longer than broad. 

 moderately constricted, sinus narrow with a dilated 

 apex; semicells truncate-pyramidate, sides and apex 

 concave, lower and upper angles broadly rounded. 

 Side view of cell narrowly elliptic, without any median 

 constriction. Vertical view elliptic, ratio of axes about 

 1:17. Cell-wall very densely and very minutely 

 punctate-scrobiculate. 



