64 DESMIDS OF THE UNITED STATES. 



C. depressum, (Naeg.) Lund., not Bailey. Plate L, figs. 10, 



11, 12. 



Cells usually slightly shorter than wide; constriction deep; 



sinus widening outwardly ; semi-cells compressed oval ; the 



long sides flattened, the others rounded ; one ehlorophyl mass 



in each. Membrane finely punctate. 



Diameter 20-25 ft. 



Frequent in pond, Spring Lake, N. J. They are smaller in 

 size than the European form; otherwise identical. 



Bailey iu his contribution, describes another plant under 

 the same name. Naegeli's description has claim of priority, 

 hence must stand. In order to avoid further confusion, I 

 change the name of the former, and in honor of the author 

 call it C. Baileyi. 



C. Baileyi, Wolle. (C. depressum, Bailey). Plate XVI, tigs. 

 17, 18. 



" Elliptical, binate, division in the plane of the longest axis. 

 Segments entire, nearly twice a^ long as broad, rounded above, 

 very much flattened at base ;" cytioderm punctate. 



Diameter 36- 18 />.. 



Florida, (Bailey); and ponds, Mount Everett, Mass. 



" This species resembles ('. bioculatum, Breb., but the seg- 

 ment* are much closer together, and are angular, not rounded 

 at the basal extremities." ( lompare Note under C. depression. 



C. OBSOLETUM, Reinseh. Plate KLIX, fig. 12. 



( 'oils elliptic, about one-fourth more in breadth than length. 

 Deeply constricted; sinus rounded at the base, then gradually 

 narrowed towards the lateral angles of the semi-cells which 

 come close together ; semi-cells in end view elliptical ; side view 

 circular. Isthmus about one-third the diameter of the cell. 

 Membrane punctate or smooth ; ehlorophyl concentrations or 

 nuclei, two. 



Diameter 110 u.\ length 8<> u, 



I adopt Reinsch's name for this plant. In general form it 

 is the same; the two distinct nuclei also correspond, but in 

 size it is much larger and the angles of the semi-cells are not 

 at all or but slightly contracted. I collected it in a sluggish 

 streamlet, Ocean Grove, N. J. It is near C. Baileyi, but 

 differs in the form of the sinus, and in having two nuclei in 

 each semi-cell ; it is also twice the size. 



