6o 



covering the surface of a slightly stagnant pond. This pond 

 \vas ver\^ near Lake Champlain, and evidently had been a small 

 bay until cut off from the Lake by a railroad embankment that 

 ran between the pond and the Lake. As a whole, due to the 

 slightly stagnant environment, the squeezings from the material 

 were not ver\- rich in any sort of plankton. The following 

 species of desmids were identified. 



Closterium Ehrenhergii Menegh. — Quite common, and con- 

 sisting of some extra large specimens. 



Micrasterias truncata (Corda) Breb. — Rare. 



Cosmarhim undulatum Corda — Rare. 



Cosmarium punctulatum Breb. — Very common. 



Cosmarium triplicatiim Wolle — Only one specimen found. 



Staurastriim creniilatiim Nag. — Common. 



Staurastrum dilatatum Ehrenb. Very common. Together 

 with the preceding species, making up most of the material. 



2. Collected at Crooked Lake 



This collection, more fruitful than the preceding one, was 

 made at an inlet to Crooked Lake. The stony bottom of the 

 clear and fresh water was covered with a dense growth of mosses. 

 Squeezings from these mosses yielded an abundance of desmids 

 which unfortunately consisted of a quantity of several common 

 species, with other desmids occasional. The species were as 

 follows : 



Netrmm Digitus (Erhenb.) Itzigs. & Rothe. — Occasional. 



Closterium Dianae Ehrenb.^ — Occasional. 



Closterium incurvum Breb. — Rare. 



Closterium Lunula (Miill.) Nitszch. — Occasional. 



Closterium Ralfsii hybridum Rabenh. — Occasional. 



Closterium Kutzingii Breb. — Only one specimen found. 



Euastrum insulare (Wittr.) Roy — Very common, and to- 

 gether with C. pseudopyramidatum making up the bulk of the 

 material. 



Euastrum hidentatum Nag. — Common. 



Euastrum dubium Nag. — Rare. 



Micrasterias americana (Ehrenb.) Ralfs — Rare. 



Cosmarium pseudopyramidatum Lund. — Ver\^ common. 



Cosmarium punctulatujn Breb. — Common. 



Cosmarium Broomei Thwaites — Rare. 



