COSMARIUM. 29 



C. AMERICANUM, Lagh. Plate LX, figs. 15, 16. 



Cells small, sinus rather obtuse and widening outwardly ; 

 semi-cells sub-circular, the center with seven larger granules 

 (six peripheral and one central) and twelve, more or less 

 distinct, around these ; vertical view elliptic ; lateral view 

 sub -circular. Membrane smooth excepting the central 

 granules. 



Diameter of cell 22 ju length 40 ^ ; thickness 18 /i ; diam- 

 eter isthmus 6 //. 



Pond near Tewksbury, Massachusetts. 



C. WOLLEANUM, Lagh., var. GRANULIFERUM, Lagh. Plate LX, 

 figs. 1, 2. Syn. C. pseudogranatum, Wolle. Des. IT. S. 

 p. 158. 



Cell rather large, one-fourth longer than wide ; sinus 

 somewhat ampliated inwardly and outwardly 5 semi-cells 

 sub - semi - circular, base subreniform, dorsum narrowly 

 rounded, angles rounded, margins finely crenulate - dentate ; 

 in vertical view oval ; in lateral view broadly oval. Mem- 

 brane distinctly punctate. 



Diameter 54 yw ; length 66 yw. 

 Tewksbury, Massachusetts. 



The author of the present name for a Cosrnarium, G. von 

 Lagerheim, of Stockholm, Sweden, finds that we have dupli - 

 cated the name pseudograiiatum, previously used by Nordstedt, 

 hence re-names the form as above. The new variety granu- 

 liferum reminds one of C. cymatopleurum, Nord. , C. de Notarisii, 

 (Witt.) Nord., and C. capense, ]N"ord., but it is distinct. 



C. BRAUNII, forma MAJOR, Eeinsch. Plate LVII, figs. 28, 29. 



Cell small, one and one-half times longer than broad, sinus 

 narrow linear 5 sides with two emarginations ; ends truncate, 

 membrane smooth ; lateral view oval ; vertical view elliptic. 



Diameter 25-28 /* ; length 36-40 /*. 

 Ponds, Still water, Minnesota. 



C. (Euastrum,) SENDTNERIANUM, Eeinsch. Plate LVII, figs. 



30, 31. 



Cells nearly twice as long as wide ; sinus narrow linear ; 

 semi -cells nearly as long as wide, ends rounded, lateral 

 margins each with four or five crenulations ; lateral view of 

 whole cell elliptic with more or less of a constriction in the 

 middle ; end view oval. 



Diameter 25 /* ; length 44 //. 



