82 DESMIDS OF THE UNITED STATES. 



C. bierme, Nord. Plate XIX, figs. 23, 24. 



Small, about as long as wide, deeply constricted, sinus wide 

 at the mouth ; semi cells elliptic, base and hack somewhat 

 truncate ; in the centre a large verruca ; viewed from the end, 

 elliptic, with a prominent cylindrical verruca in the centre of 

 each side; lateral view, obovate furnished with a similar ver- 

 ruca. Membrane smooth. 

 Breadth 13//.; length 14//.. 



Denmark Pond and Budd's Lake, N. J. 



< '. SCHMEPHACKEANUM, < mm. Plate XVIII, 6g8. 14, 15. 



Very small, subquadrate, as broad as 1 < 1 1 ^ . smooth, entire. 

 deeply constricted ; semicells depressed, ends broadly truncate. 

 <ir plane-convex ; sides convex, often projecting at an obtuse 

 angle; centre more or less inflated. 



Breadth 12 ,".; it' not equal, slightly less in length. 



Occurs occasionally in large numbers, hut more frequently 

 it is found singly in pond- of Pennsylvania, New Jersey, 

 Massachusetts, Minnesota. 



lis with a central inflation, membrane granular, 

 C. ORNATUM, Kalfs. Plate XVIII. figs. 39-45; Plate XLIX, 



figs. 22-24. 



Cells of nearly equal length and breadth, constriction deep, 

 narrow; Bemicells with a somewhat reniform base, angles 

 broadly rounded, end truncate; sides inflated below, and con- 

 tracted and concave near the end, thus producing a truncate 

 projection which in end view forms a rounded lobe; mem- 

 brane rough with pearly granule- which give a dentate ap- 

 pearance to the margin. 



Diameter 33-45 //. 



Not uncommon ; probably no form is more generally dis- 

 tributed throughout the earth. It is variable in size, in the 

 arrangement of the central granules and in the projection. 



Var. protractum. Plate XLIX, fig. 22; Plate XVII, fig. 29. 



The figure i Plate XLIX i represents a form collected July, 

 1883, by my friend, Dr. Kitchel, in Lake Minnetonka, Minn. 

 He found it freely intermingled with the typical form (fig.23). 

 Tt is in all its parts except the more protracted ends, bo like 



