176 FRESH-WATER ALG.ZE OF THE UNITED STATES. 



OPHIOCYTIUM CAPITATUM, Wolle. 



Cells short, five to six times longer than broad, nearly 

 straight, or arched, with both ends more or less incurved 

 and most frequently somewhat enlarged, rounded, a spine 

 on each end. 



Diameter of cells, 6-9 //. 



Not infrequent in ponds, East and West. 

 Plate CLVIII, figs. 3-7, different forms. 



OPHIOCYTIUM PARVULUM, (Perty) A.Br. 



Cells small, variously curved, and often interwoven into 

 masses, both ends rounded, no spines. Near O. cochleare, 

 but smaller and spineless. 



Syn. Brochidium parvulum, Perty. 



i 

 OPHIOCYTIUM CIRCINATUM, Wolle. 



Cells cylindrical filiform, long, circinate, repeatedly coiled, 

 ends obtusely rounded, no spines. 



Diameter of cells, 10-13 yw. 



Specimens frequent in pond near Minneapolis, Minn. 

 Coll. Miss E. Butler. 



Plate CLVIII, figs. 15-18, four cells of ordinary appear- 

 ance. 



OPHIOCYTIUM CUSPIDATUM, (Bailey) Eab. 



Cells large, smooth, crescent-shaped, Closterium-like, ends 

 mucronate. Four to five times longer than broad. 



Diameter 50 /* ; length 150-165 ^ length of spines, 15 /*. 



Syn. Closterium cuspidatum, Bailey. 



Rather rare Bailey found it in several localities ; person- 

 ally collected it only in Gilder Pond, Massachusetts, but re- 

 . ceived specimens from Minnesota and from California. 



Plate CLVIII, figs. 1, 2, after specimens from Gilder Pond, 

 Massachusetts. 



Genus 48, CHARACIUM, A. Br. 



Cells always attached ; at one end usually distinctly stipitate, 

 variable in form ; oblong, ovate, pyriform, fusiform, etc. Cell 

 contents green, homogeneous or granular ; zoogonidia succeeding 

 division of the cytioplasm, more or less numerous, occupying 

 the whole of the cell, at length greatly agitated, escaping by a 



