0O8MARIUM. 71 



three papillae on each side (omitted in the figure); lateral view- 

 circular, with end truncate, and two rows of granules extend- 

 ing from the angles of the truncate end of one semieell to 

 those of the other; the margins of the sides ornate with three 

 papillae. 



Nordstedt made this form, found by him in Norway, a 

 variety of Lundell's C. monomazum, which has not occurred 

 here; the other C. polymazum, is frequent in Denmark Pond, 

 N. J. 



C. I>n\\i:u.ii, Wolle. Plate XVI, figs. 11. 12. 



Cells nearly a- long as wide suborbicular ; sinus narrow 

 gaping; semioells somewhat flattened, semicircular with 

 angles rounded ; margin formed ofaboul eighteen large pearl- 

 like granules; area smooth with a series <>f three larger granules, 

 or papilla; in the centre. End view oval, three papillae on 



each side. 



Diameter 37-45 fi. 



Pound in collections made by J. Donnell Smith in Florida, 

 1879. 



C. TAXICHONDRUM, Lund. Plate X Y 1 . figs. 32-34. 



Cells suborbicular, slightly longer than broad; sinus deep, 

 narrow, linear, barely widened at the mouth ; semioells semi- 

 circular, margin of base nearly straight, membrane thickened 



at the angles; face ornate with a single large granule ai 

 the isthmus, and two somewhat arched rows near the dorsal 

 margin, one with three ami the other with five or six granule.-; 

 seen from the vertex, elliptic with five or -i\ granules OH each 

 side; cytioderm punctate; isthmus one-fourth of thediameter 

 of the cell. Chlorophyl nuclei two. 

 Diameter 40-50 u. 



Occurs frequently in ponds, northern New Jersey and 

 Pennsylvania. 



C. PSEUDOTAXICHONDRUM, Nord. Plate L, tigs. 22, 2o. 



Scarcely as long as broad, deeply constricted, sinus consid- 

 erably widened outwardly ; semioells semicircular with the 

 middle more or less truncate or depressed ; the angles some- 

 what thickened and often terminating in a tooth-like point; 

 above the basal line is an arched transverse series of four 



