86 DEs.MIDS OF THE UNITKI) STATES. 



Var. TUMIDUM, Wolle, has the sides, front view, not parallel, 

 but swollen or rounded. 

 Diameter 20-25 ^. 



Rhode Island (Olney), Florida (Bailey). 



Frequent in Pennsylvania, Now Jersey, Massachusetts. 



C. ORTHOSTICUM, Lund. Plate XXI. figs. 4, 5. 



Cells slightly more in length than the diameter, deeply 

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

 rounded, base and dorsuni nearly straight, coarsely verru- 

 cose ; verrucae in 6-8 vertical series; from the vertex elliptic; 

 verrucose on or near the margins, area punctate; from the 

 side, circular. Chlorophyl nucleus single. 

 Diameter 20-30 yu. 



Ponds, northern New Jersey and Mount Everett, Mass. 



C. ELEGANTISSIMUM, Lund. Plate XVII, 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 emarginat<- verrucae 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 p. 



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 uudulate-crenate, ends broadly truncate; semi- 

 cells, base somewhat reniform, sides converging from the 

 base to the broadly truncate end ; angles rounded ; cytioderni 

 smooth or finely granulate. 



Diameter 25-30 ;u. 



Met with rather rarely in shallow pools and on dripping 

 rocks. 



C. HAMMEKI, 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 



