12 DESMIPS of THE UNITED STATES. 



C. strigosum, Ehrb. Plate VI, tigs. IS, 14: and Plate LIII, 



tigs. 9, 10. 



Long fusiform, at the ends somewhat bent, 19-24 times as 



long as broad, .-lightly tapering from the middle to the thin, 



finely rounded apices. Vacuole small and indistinct. Cytio- 



derm colorless, smooth. 



Diameter 1016 fi. 



Pond waters, Pennsylvania and New Jersey. Plate LIII, 

 figs. 9, 10, represent a fruiting form, collected in abundance 

 near Ocean Beach, July, '83. In form near C. parvulum Init 

 proportionately so much longer than that species, I take it for 

 a variety of C. strigosum. Diameter of cells 10 ft. length 

 200 ft.; twenty times longer than wide. 



Section III. ' ells more or low falcate; dorsum and ventral margins l>th con- 

 vex, arched in tli' Bame direction, ml- tapering. \ A. forms slightly curved; 

 B. forms stronglj curved, sometimes almost semi-circular. 



I . striolai i m. Ehrb. Plate V I. figs. 8, 20. 



Cells slightly bent, 816 times longer than broad, ends 

 reduced to about one-fourth the largest diameter, apex obtusely 

 rounded. Vacuole full size, containing man} active granules. 

 Cytioderm of older forms, reddish brown, distinctly striate. 







X\ gospore orbicular, smooth. 



Diameter 30-48 ". 



Frequent in shallow pools. 



1 find three varieties, the one 6-8 times longer than hroad 

 Plate Vl.fig - : another 10-15 (Plate VI, fig. 20); and the 

 third only 4-") time.- longer than broad. They may l>e recog- 

 nized as varieties, intermedium, lialf-: dongatum, Kali; and 

 tumidum, Rab. The latter is very near Nord's. subcostatum. 

 The variety elongatum i- more -lender and more delicately 

 striate than the others. 



C. COSTAG i If, < oi-.la. Plate V 1. fig. 1 9. 



Fusiform, more or less curved, 68 diameter- in length, 

 ends rounded; tapering from the middle to about one-third 

 the largest diameter; vacuole large, containing many dancing 

 granules. Membrane in front view has 5, or rarely 68 

 longitudinal striae or costae. Zygospores spherical or ovate. 



I diameter 63 -70 



Frequent in marsh pools and the like localities, 



