66 BRITISH DESMIDIACE.E. 



2. Netrium Nagelii (Breb.) 

 (PI. VII, figs. 4, :>.) 



Closterium (Netrium) Digitus Nag. Gatt. einz. Alg. 1849, p. 1(>7, t. 0, f. D. 



Penium Nagelii Breb. apucl Arch, in Pritch. Infus. 1861, p. 7ol : Babenh. 

 Flor. Europ. Alg. 1868, III, p. 119 ; Cooke, Brit. Desm. 1SS6, p. -12, t. 1'i, 

 f. 4; Schmidle Beitr. alp. Alg. 1895, p. 311, t. 1-4, f. 31 ; West ,V G. S. 

 West, Alg. S. England, 1897, p. 479. 



Cells of medium size, about 4^ times longer than 

 their diameter, not constricted, oblong-lanceolate, 

 apices broadly but truncately rounded; chloroplasts 

 axile, with from four to six longitudinal radiating 

 plates which are notched at the free margins ; some- 

 times large terminal vacuoles are present containing a 

 number of moving granules. 



Zygospore unknown. 



Length 115-1 60 /x; breadth 25-34 /.i. 



ENGLAND. Sutton Park, Warwick (Willy). Enbridge 

 Lake (Roy). New Forest, Hants ! 



WALES. Capel Curig ! (CooJce $ Wills). Moel Sia- 

 bod, Carnarvonshire ! 



SCOTLAND. General (Itoy fy Bissett). Rhiconich, 

 Sutherland ! Moidart, Inverness ! Near Tarbert, 

 Harris, Outer Hebrides ! 



IRELAND. Dublin and Wicklow (Archer). 



Geogr. Distribution. France. Germany. Austria. 

 Switzerland. Norway. Sweden. Lapland in Russia. 

 Australia. New Zealand. East Africa, Brazil. 



This species hears considerable resemblance to N. Digitus, 

 but is of smaller size and somewhat narrower. It is a very 

 uncommon plant in the British Islands and we have not seen 

 many specimens of it. 



3. Netrium oblongum (De Bary) Lutkem. 

 (PI. VIII, figs. 1-3.) * 



Penium oblongum De Bary, Conj. 1858, p. 42, 73, t. 7 G, f. 1, 2 Eabenh. 



Flor. Europ. Alg. 1868, III, p. 119, fig. xylogr. p. 102 ; Delp. Desm. subalp. 



1877, p. 86, t. 15, f. 40-42 ; ? Wolle, Desm. U.S. 1884, p. 34, t. 5, f. 17; 



West & G. S. West, Alga-fl. Yorks. 1900, p. 45; Alg. N. Ireland, 1902, 



p. 21. 

 Netrium oblongum (De Bary) Lutkem. Zelluiembr. Desmid. 1902, p. 407. 



