Freshwater Algse of North Wales. By Wm. West. 
Class Cyanophyce^ or Phycochromace^. 
Sub-class Nostochine^. 
Order Nostocace^. 
Genus Nostoc Vaucb. 
N. maeros'jgormn Meneg. C. 
Genus Sifhserozxjga (Ag.) Kalfs. 
S. elastica (Kalfs). F. 
Genus Anahsena Bory. 
A. Smithii (Thur.) Nord. and Wittr. Twll Du. 
Order Eivulariace^. 
Genus Bivularia Eotb. 
R. echinata (Eng. Bot.). Twll Du. 
Order Scytonemace^. 
Genus Tolypothrix Ktz. 
T. mgagropila Ktz. C. 
var. pygmsea Ktz. Twll Du. 
T. coaciilis Ktz. C. 
Genus Scytonema Ag. 
S. myochrous Ag. B., Bettws-y-coed, C. 
Genus Stigonema Ag. 
S. panniforme Ag. C., Twll Du. 
S. mamillosum Ag. 0. 
The last two species are probably lichens. 
Order Oscillariace^. 
Genus Oscillaria Bose. 
O. tenerrima Ktz. C. 
0. tenuis Ag. 0. 
0. limosa Ag. P. 
0. irrigua Ktz. Do. 
0. nigra Yauch. D., Do. 
0. Frdlichii Ktz. C., Twll Du, Bodorgan. 
Genus Lynghya Ag. 
L. littoralis Carm.. Llandudno, in a pool near the sea. 
L. vulgaris Kirch. A., Do. 
