COSMARIUM. 81 



Loch, Bogwartle, Aberdeen ; Dalbrake, Kincardine ; 

 Menmuir and Barrelwell near Brechin, Forfar (lioij \ 

 Bissett). HOY, Orkneys ! 



Geor/r. Distribution. France. Gralicia in Austria 

 (form). Italy. Xorwav. Sweden. Denmark. Born- 



/ */ 



holm. Poland. X. Eussia. Afghanistan. India. 

 Madagascar (yar.). Central Africa (yar.). E. Africa 

 (yar.). Australia (yar.). United States. 



C. abruptum should be compared with C. Blyttii, the Desmicl 

 to which it is very probably most nearly related. The 

 existence of C. aJhruptivm var. grnnulatum "\V. & Gr. S. West 

 (' Alg. Madag.' 1895, p. 65, t. 7, f. 32), with a wide geogra- 

 phical distribution, emphasizes the closeness of this relationship. 



102. Cosmarhim sexangulare Lund. 

 (PL LXXII, fig. 3.) 



Cosmarium sexangulare Lund. Desm. Stiec. 1871, p. 35,, t. 2, f. 23; Delp. 



Desrn. subalp. 1877, p. 15, t. 7, f. 69-73 [figures not typical" ; Wolle, 



Desm. U. S. 1884, p. 63, t. 16, f. 8, 9 [figures not good] j De Toni, Syll. 



Alg. 1889, p. 954; Eoy & Biss. Scott. Desm. 1894, p. 174; Nordst. Index 



Desm. 1896, p. 233. 

 Ursinella sexanfjv.laris Kuntze, Eevis. gen. plant. 1891, p. 925. 



Cells of moderate size, about 14- times longer than 

 broad, deeply constricted, sinus very narrow, with a 

 dilated apex ; semicells transversely elliptic-hexagonal, 

 angles rounded, upper lateral margins very slightly 

 concave, apex truncate and straight. Side view of 

 semicell subcircular. Vertical view elliptic, ratio of 

 axes 1 :1'5. Cell- wall very finely punctate. Chloro- 

 plasts one in each semicell, axile, with one pyrenoid. 



Zygospore unknown. 



Length 42 p, ; breadth 34-36 ^ ; breadth of isthmus 

 11-12 p; thickness 22-24'5/x; breadth of apex 

 15-18/x. 



SCOTLAND.- -Loch Hempriggs, Caithness ; Scotston 

 Moor, Brimmond, Slewdrum, near Aboyne, and 

 Pittellachie in Cromar, Aberdeen; Crathes, Loch 

 Loirston, and Palely Hill, Kincardine (Roy $ Bissett). 



Geoyr. Distribution. Germany. Galicia in Austria. 

 Hungary. Sweden. Poland. N". and S. Russia. 



VOL. in. 6 



