COSMARIUM. 143 



Length 87-1 '28 /x, ; breadth 76-101 /x: breadth of 

 isthmus 20-23 //,. 



IRELAND. Carrantuohill, Kerry ! 



t/ 



Geoyr. Distribution. Gralicia in Austria. Poland. 



8. Cosmarium perforatum Lund. 

 (PL LVIII, figs. 4, 5.) 



Cosmarium perforatum Lund. Desin. Suec. 1871, p. 40, t. 2, f. 16; Wolle, 

 Freshw. Al?. U.S. 1887, p. 28, t. 57, f . 32 ; De Toni, Syll. Alg. 1889, 

 p. 977 ; West, Alg. W. Ireland, 1892, p. 144 ; Alg. Eng. Lake Distr. 

 1892, p. 724 : Liitkem. Desm. Attersees, 1893, p. 556 ; Eoy & Biss. 

 Scott. Desni. 1894, p. 171; Nordst. Index Desin. 1896, p. 199; West & 

 G. S. West, Alg. N. Ireland, 1902, p. 33. 

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

 Cosmarium perforatum a. typicum Gutw. Flor. Glon. Okolic Lwo\va, 1891, 

 p. 48. 



Cells of medium size, angular-subcircular, a little 

 longer than broad, moderately constricted, sinus some- 

 what open, widening outwards from an acute apex ; 

 semicells subpyramidate-semicircular, basal angles 

 rounded-truncate, sides almost straight for a short 

 distance, then converging to the subtruncate or sub- 

 retuse apex. Side view of semicell subcircular, broad 

 at the base and slightly retuse at the apex. Vertical 

 view elliptic with pointed poles, ratio of axes about 

 1 : 1*56. Cell- wall rather thick, punctate, with a sub- 

 triano'ular area in the centre of the semicells near the 



o 



isthmus furnished with about 20 small scrobiculations. 

 Chloroplasts axile, each with two pyrenoids. 



Zygospore unknown. 



Length 60-75/0,; breadth 5 7-63 ^; breadth of 

 isthmus 26-36 JJL : thickness 38-40 /x. 



ENGLAND. Bowness, Westmoreland ! 



SCOTLAND.- -Loch Ruthven, Inverness ; Dalbagie and 

 Loch Ullachie near Ballater, near Castleton, and Birse- 

 more, Aberdeen (Roy $ Bissett}. Dumfries ! 



IRELAND. Loughs Akibbon, Grartan, and Sproule, 

 Donegal! Ballynahinch, Lough Derryclare, Lakes E. 

 of Lough Bonn, and small lakes Clifden to Round- 

 stone, G-alway ! 



