294 
Slightly smaller than the original specimens from Brazil. Diam. 
=50y; length=50y; isth=13y. Fig. 30. 
* C. quadrum Lund. forma. (359.) Plymouth, N. H. Seems 
to be near var. minus Nordst. Semi-cells decidedly reniform at 
base; sometimes slightly retuse at the apex. Diam.—40 4; 
length=44 yp; isth—=14 yp. Fig. 22. 
* C. Raciborskii Lagerh. (365.) Meredith, N. H. Very rare. 
The membrane seems faintly granulate in the upper part of the 
semi-cell, but as the granules were not distinct they were not 
shown in the drawing. This agrees with the type in shape and 
surface, but differs slightly in the inner part of the sinus. Diam. 
=50y; length=44 y; isth—=21y. Fig.20. 
* C. subspectosum var. validius Nordst. (433.) Whitmore Lake, 
Michigan. Occasional. Diam.=48 »; length=62 y; isth—14/- 
Differs from the original description in having seven vertical rows 
of granules on the inflation and in the fact that they are in more 
or less definite horizontal rows also. This hardly seems sufficient 
ground for separating it as a new variety. Fig. 33. 
*C. synostegos Schaarschm. (437). Bridgeport, Conn., and 
Sisson, Cal. Common but very minute. The specimens from 
Bridgeport average 10 » in diameter, the others 8 » with length= 
11, thick=5 ». The angles in the Californian specimens do not 
appear cuspidate. In most cases the sinus gapes little, if at all- 
This may prove to be a distinct species. Fig. 29. 
*C. tetragonum Naeg. var. Lundellii Cke. (512). Ithaca, N. Y- 
Occasional. Diam.=24y; length=42; th.=16y. Fig. 21. 
*C. Turpini Breb. var. podolicum Gutw. (346). Baton Rouge, | 
La. Slightly smaller than Gutwinski’s measurements, but other- 
wise the same. Diam. 4o #; length=46p; th.=264 isth.= 
124. Fig. 18. 
Staurastrum brachiatum Ralfs. Duval Co., Fla. Rare. 
St. brevispinumBreb. Staten Island, N. Y., and Sisson, Cal. 
Frequent. 
St. commutatum Kiitz. (349). Duval Co., Fla. Rare. 
Sz. grande Bulnh. Bridgeport, Conn., and Meredith, N. H. 
Diam.=68-78 p. 
St. irthedrale Wolle. Frequent in collections from Florida, 
also from Staten Island and Ithaca, N. Y. Diam.=28—30 /- 
