6i 



Cosmarium octhodes Nordst. — Rare. 



Cosmarium ornatum Ralfs — Rare. 



Cosmarium triplicatiim Wolle — Occasional. 



Cosmarium. isthmium West — Only one specimen found. 



Staiirastrum dilatatum Ehrenb. — -Rare. 

 Besides these desmids, the material was particularly rich in 

 other plankton. Most numerous were Pediastrum tetras (Eh- 

 renb.) Ralfs, Pediastrum duplex Meyen, Sorastrum americaniim 

 (Bohlin) Schmidle, and Coelastriim microporum Nag. 



3. Collection' at Grafton 



At Grafton, the collection came from a roadside swamp, 

 almost destitute of water, but with the pools containing sub- 

 merged sphagnum scattered among the tussocks of dry grass. 

 Squeezings from this submersed sphagnum netted the following 

 species : 



Closterium Dianae Ehrenb.^ — Common. 



Closterium rostratum Ehrenb. — Only one specimen. 



Closterium intermedium Ralfs — Common. 



Closterium didymotocum Corda — Occasional. 



Closteruim Lunula (Miill.) Nitzsch. — Occasional. 



Pleurotaenium trabecula (Ehrenb.) Nag. — Common. 



Tetmemorus Brebissonii (Menegh.) Ralfs — Rare. 



Euastrum ohlongum (Grev.) Ralfs — Common. 



Euastrum ansatum Ralfs — Common. 



Micrasterias laticeps Nordst. — Occasional. 



Micrasterias truncata (Corda) Breb. — Rare. 



Micrasterias radiata Hass. — Very abundant. 



Micrasterias denticulata Breb. — Common. 



Micrasterias rotata (Grev.) Ralfs — Rare. 



Cosmarium pseudoconnatum Nordst. — Occasional. 



Cosmarium pseudopyramidatum Lund. — Common. 



Cosmarium, moniliforme Ralfs. — Rare. 



Cosmarium contractum Kirch. — Rare. 



Cosmarium ovale Ralfs — Very abundant and consisting of ex- 

 cellent specimens. 



Staurastrum crenulatum Nag. — Common. 



Hyalotheca dissiliens (Smith) Breb. — Rare. 



