86 DKSMIDS OF THE UNITKD STATKS. 



Var. TUMiDtiM, ^Yolle. has the sides, front view, uot parallel, 

 but swollen or rounded. 

 Diameter '20-'25 lu. 



Ehode Island (Olney), Florida (Bailey). 



Frequent in Pennsylvania, iXew Jersey, Massachusetts. 



C. ORTHOSTicuM, Luud. Plate XXI. figs. 4, 5. 



Cells slightly more in length than the diameter, deeply 

 constricted, sinus narrow linear ; semi-cells subelliptic, sides 

 rounded, base and dorsum nearly straight, coarsely verru- 

 cose; verrucae in 6-S vertical series; from the vertex elliptic; 

 verrucose on or near the margins, area pl^nctate ; from the 

 side, circular. Chlorophyl nucleus single. 

 Diameter 20-30 yu. 



Ponds, northern New Jersey and Mount Everett, Mass. 



C ELEGANTissiMUM, Lund. Plate XYII, figs. 8, 9. 



Cells two to two and one-half times longer than broad, 

 perfectly cylindrical, ends arched : slightly constricted ; 

 viewed from the vertex, circular; margins verrucose-crenate; 

 membrane with emarginati> verrucas disposed in twenty-two 

 longitudinal series, of which about nine are visible in front 

 view ; these are arranged transversely also, in eight or nine 

 series on each semi -cell ; the same contains two chlorophyl- 

 lous nuclei. 



Diameter 29-33 //. 



I found this plant in collections made in Florida ; it differs 

 somewhat in size from Lundell's Swedish form, being more 

 variable in length, varying from two to three diameters ; the 

 number of longitudinal series, if actual series, is greater than 

 specified ; the transverse series agree. 



C. NOTABILE, Breb. Plate XIX, fig. 11. 



Length of cell nearly equal to two diameters, margins 

 somewhat undulate-crenate, ends broadly truncate ; semi- 

 cells, base somewhat reniform, sides con^•erging from the 

 base to the broadly truncate end ; angles rounded ; cytioderm 

 smooth or finelj' granulate. 



Diameter 25-30 ju. 



Met with rather rarely in shallow pools and on dripping 

 rocks. 



C. Hammeei, Eeinsch. Plate XXI, figs. 27, 36-38. 



Small, smooth ; semi-cells in form of a truncate cone, the 

 end either straight or slightly retuse, the sides rounded 

 below and slightly concave above ; the truncate ends about 



