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Palmodactylon varium, Nâg. 



Scenedesmus obliguus (Turp.), Kiitz. 



Pediastrum tétras (Ehrenb.), Ralfs. 



Trochiscia reticularis (Reinsch), Hansg. 



Oocystis Naegelii, A. Br. 



Pleurococcus angulosus, Menegh. 



Characium Pringsheimiî, A. Br. 



Gloeocystis infusionum (Schrank), W and G. S. West. 



Protoderma viride, Kùtz. 



Gongrosira viridis, Kiitz. 



Radiofilum ffavescens, G. S. West. 



Microthamnion Kûtzingianum, Nàg. 



Aphanochaete repens, A. Br. 



Chaetosphaeridium globosum (Nordst.), Kiebahn. 



Bulbochaete nana, Wittr. 



Closterium acerosum (Schrank), Ehrenb. 

 » Kutzingii, Bréb. 



Gosmarium sexangulare, Lund. f. minima, Nordst. 

 » undulatum, Corda var. minutum, Wittr. 



Staurastrum brevispinum, Bréb. 



Ophiocytium Arbuscula (A. Br.), Rabenh. 

 » 7//,v?e (v. Istv.), Heering. 



» parvulum (Perty), A. Br. 



Microcystis marginata, Menegh. 



Oscïllatoria tenuis, Ag. 



Navicula viridis (Nitzsch), Kiitz. 

 » mesolepta, Ehrenb. 



Stauroneis Phœnicenteron, Ehrenbg. 



Amphora ovalis, Kiitz. (small form). 



It will be well 1,o compare briefly the algai flora of Barton"s 

 pond with that of Abbot's pool. The two ponds resemble one 

 another only superficially, the points of similarity being the 

 abundance of filamentous Conjugatae, the relative paucity of 

 Desmids, the important part played by Diatoms in the vvinter- 

 montlis and the scanty development of Cyanophyceae. The 

 points of différence are more numerous : the filamentous Conju- 

 gates are represented by three gênera in Bartbn's pond, while 

 Spirogyra is alone of importance in Abbot's pool ; species of 

 Oedogonium are of quite minor importance in Abbot's pool ; 

 Cladophora is completely wanting in Barton's pond, while 

 Microspora and Conferva are important gênera; Melosira 



