COSMAIUUM. 53 



Forma depressa West & G. S. West. (PL LXIX, 



figs. 28, 29.) 



C. Norimbergense Eeinsch forma depressa West & G. S. West, Welw 

 Afric. Fresliw. Alg. 1897, p. 119 ; Freshw. Chlorophy. Koh Cham-, 1901 ' 

 p. 175. 



Cells about as long as broad, semicells depressed. 



Length H-15'5//,; breadth 11-14/x; breadth of 

 isthmus 3 '5-5 p.. 



IRELAND.- -Small lakes between Clifden and Bound- 

 stone, and Lough Derryclare, Gralway ! 



Geogr. Distribution. Ceylon. Burma. Siam. Central 

 Africa. 



Another form of this species, as yet not found in the British 

 Islands, is forma elongata West & GL S. West (' Welw. Afric. 

 Freshw. Alg./ 1897, p. 119, t. 368, f. 4, 5 ; C. emguum Arch, 

 var. Norimbergense Schmidle, in 'Flora, Ixxviii, 1894, p. 56, 

 t. 7, f. 17). This form is almost twice as long as broad and 

 the upper angles of the semicells are not quite so rounded : 

 length 16-18 // j breadth 9'5 ju ; breadth of isthmus 3 /.. ; thick- 

 ness 7/.t. 



78. Cosmarium repandum Xordst. 

 (PI. LXIX, fig. 30.) 



Cosmariiun i-epandu,n Xordst. in Botan. Xotis. 1887, p. 162; Freshw. Alg % . 



X. Zeal. 1888, p. 58, t. 6, f. 14 ; Mask. Further Xotes New Zeal. Desm. 



1889, p. 16, t. 2, f. 21 ; De Toni, Syll. Alg. 1889, p. 971 ; Xordst. Index 



Desm. 1896, p. 224. 

 Ursinella repanda Kuiitze, Eevis. gen. plant. 1891, p. 925. 



Cells of medium size, about 1J times longer than 

 broad, deeply constricted, sinus narrowly linear with 

 a dilated apex ; semicells transversely trapezoid-obloni; , 

 widest above their middle, sides distinctly divergent, 

 lower angles obtuse, apex arched from the widest part 

 of the semicell where the upper angles are broadly 

 rounded, usually flattened at the middle of the arch. 

 Side view of semicell subcircular. Vertical view 

 elliptic, ratio of axes about 1 : To, poles rounded, but 

 when viewed obliquely (and especially from the base) 



