COSMARIUM. 7 



membrane punctate; in vertical view elliptic granulate 

 around the margin ; in lateral view circular. 

 Diameter 33-35 p. ; length 39-42 /v. 

 Tewksbury, Massachusetts. 



C. KITCHELII, Wolle. Plate XXI, figs. 1-3. 



Cells suborbicular, about one-fourth longer than broad, 

 deeply constricted ; sinus narrow linear ; semi-cells semicir- 

 cular, margins crenulate, with about 18 crenae ; within, two 

 concentric rows of granules corresponding with the crenae ; 

 area smooth excepting two, rarely three, transverse rows of 

 three larger granules each, in the middle ; viewed from the 

 vertex, ovate-elliptic with three larger granules on each side, 

 and four series of smaller granules extending from end to 

 end ; lateral view circular with two granules on each side, 

 and four central series. 

 Diameter 40 yw. 



Collected by Eev. H. D. Kitchell in a pond near Ham- 

 monton, New Jersey. This species is readily recognized by 

 the large marginal granules, end and side view, and by the 

 four parallel central series of smaller granules. It bears 

 some resemblance to C. polymrtzum, but differs in the central 

 granules and in the double row of marginal smaller granules. 



C. TRACHYPLEURUM, Lund. Plate XIX, figs. 26-29. 



Cells about one-fourth longer than the diameter ; isthmus 

 narrow; sinus narrow, enlarged outwardly; semi-cells sub- 

 reniform ; ends truncate, nude in center ; the margins of the 

 sides armed with five or six conical spines ; the area close to 

 the margin, is set with numerous conical spines arranged in 

 short concentric series ; the middle is ornate with seven 

 granules, six in a circle and one in the center ; between 

 these granules punctate ; viewed from the vertex, elliptic 

 with three prominent granules on each side ; within the 

 margin, and near it, is a series of conical granules ; lateral 

 view circular. Chlorophyllous nuclei, two. 



Diameter 33-40 /.(. 



Frequent in ponds, eastern Pennsylvania and New Jersey. 



C. TRIPLICATUM, Wolle. Plate XXII, figs. 3-6. 



Cells about one- fourth longer than broad, subrectangular ; 

 angles obtuse ; sinus between the semi-cells linear ; margins 

 irregularly granulate crenate ; membrane rough with larger 

 and smaller granules : the larger ones arranged in series of 

 three ; three on the margin of each of the three superior 



