COSMARIUM. 17 



Alg. 1889, p. 890 [" forma minus "] ; West, Alg. N. Yorks. 1889, p. 293 ; 

 Gutw. Flor. Glonow Galic. 1892, p. 14 ; Eoy & Biss. Scott. Desm. 1894, 

 p. 169 ; West & G-. S. West, Alga-fl. Yorks. 1900, p. 81. 

 Dysphinctium notabile (Breb.) Hansg. forma minor (Wille) Sclimidle, 

 Weit. Beitr. Algenfl. Eheineb. ti. Schwarzwald. 1895, p. 72. 



A small form somewhat less constricted, with 

 slightly more convex sides and truncate apices. 



Length 24-30 p ; breadth 15-20 /* ; breadth of isth- 

 mus 12-16 M; thickness 15-18^. 



ENGLAND. Mickle Fell, N. Yorks ! 



SCOTLAND.- -Craig-an-Lochan, Perth ! 



IRELAND.- -Near Westport, Mayo ! 



Geogr. Distribution. Germany. Bohemia and Galicia 

 in Austria. Nova Zembla. 



Forma media Gutw. (PI. LXVI, figs. 18, 19.) 



C. notabile Breb. forma media GutAv. Wahr. d. Prioritat, 1890, p. 66 ; 

 Flora Glon. Okolic Lwowa, 1891, p. 39, t. 1, f . 10 ; West & G. S. West, 

 Alg. S. England, 1897, p. 488. 



Sinus somewhat more closed than in the type ; 

 vertical view slightly tumid at the middle on each side. 



Length 25-36 /x; breadth 16-24/i; breadth of 

 isthmus 9-12 //, ; thickness 13-1 7 ft. 



ENGLAND.- -New Forest, Hants ! 



Geogr. Distribution.- -Galicia in Austria. 



Grutwinski states that this form also differs in having more 

 rounded apices when seen in the side view ; but we find the 

 apices of the type-form to be commonly rounded when seen 

 from the side. 



59. Cosmarium tetragonum (Nag.) Arch. 

 (PI. LXVI, figs. 20, 21.) 



Euastrum (Cosmarium) tetragonum Nag. Gatt. einz. Alg. 1849, p. 119, 



t. 7 A, f . 5. 

 Cosmarium tetragonum (Nag.) Arch, in Pritch. Iiifns. 1861, p. 732; 



Kabenh. Flor. Europ. Alg. Ill, 1868, p. 164 ; Cooke, Brit. Desm. 1887, 



p. 98, t. 37, f. 17 ; De Toni, Syll. Alg. 1889, p. 959 ; West, Alg. N. Yorks. 



1889, p. 292 ; Alg. N. Wales, 1890, p. 289 ; Alg. Engl. Lake Distr. IS'Ji', 



p. 72-i; Eoy & Biss. Scott. Desm. 1894, p. 176; Nordst. Index Desmid. 



1896, p. 253 ; West & GK S. West, Alg. S. England, 1897, p. 485; Alga-fl. 



Yorks. 1900, p. 81. 

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



Cells rather small, about twice as long as broad, 

 deeply constricted, sinus narrowly linear, with a slightly 



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