ID DESMIDS OF THE UNITED STATES. 



flattened cell permits the striae of both surfaces to be visible 

 together; I will venture to suggest the possibility that Prof. 

 Kiitzing's drawing may have been taken from a cell in that 

 condition." 



The correctness of Kiitzing's observations is readily estab- 

 lished by an examination of the plants as found in Gilder 

 and other ponds on Mt. Everett. They are cylindrical and 

 may be rolled over to display the decussated striae on every 

 side alike. 



C. ANGU8TATUM, Kg. Plate VI, figs. 21, 22, 23. 



< Sells sublinear, 1618 times longer than wide very slightly 

 attenuated; ends obtusely rounded. Cells present 15 some- 

 what prominent longitudinal striae; 2 or 3 transverse bands 

 r striae arc also frequently distinct ; vacuole subremote from 

 the apex, small. Dried specimens brownish yellow. 



A variety is frequent with the striae loosely crossing each 

 other, decussately. 

 I diameter 1 525 ". 



Pond-, Berkshire Mountains, Mass 



Sectioh [I. Cells slightb bent, the back (dorsum) more or lew convex, the 



opposite (ventral) side almost straight, distinctly attenuated fi i the middle to 



the i ml-. Zygospore globular, - oth. 



C. Ij m i \. Ehrb. Plate L, lig. 26. 



( Jells large, semilunar, 5-6 times longer than broad, smooth, 

 or very finely striate, indistinct, back high convex, lower side 

 9traightish, end- attenuated, rounded. Chlorophyl globules 

 numerous ; vacuole usually distinct and contain- many 

 actively moving granules. 

 Diameter 80-1 10 ". 



Frequent in Bmall pond-. 



The figure is nol a L r ""d typical form. It should uol be 

 curved bo much at (he end. 



I . I i i (JMis, Ehrb. Plate VI, figs. 17, 18. 



< lells smooth, stout, semi lunate ; >u(\- broadly rounded. 



Ehrenberg's figure represents this species about five times 

 longer than broad; in form somewhal resembling C. Lunula, 

 not so large, and lower side more concave. Ehrenberg col- 

 lected if in the State of New York. The figures are from 



plant> found in New Jersey and Pennsylvania. They are 

 evidently closely allied to C. Lunula. 



