100 DESMIDS OF THE UNITED STATES. 



E. ampullaceem, Ralfs. Plate XXVIII, figs. 8-11. 



Semicell less in length than breadth, base inflated, not 

 emarginate, bnt having on each side, near the middle, a small 

 tubercle, or prominence; end lobe exserted and dilated, its 

 notch linear, or somewhat gaping. Membrane minutely 

 punctate. Transverse view, four inflations on each side and 

 one at each end. 

 Diameter 6275 u. 



Not as common as the preceding, but not rare. 



E. ai-fink, Ralfs. Plate XXV, figs. II, 12. 



About twice as long as wide ; semicell- three lobed ; basal 

 lobes somewhat emarginate ; intermediate between them and 

 the end lobe <>n each side is a prominence, the upper margin of 

 which is nearly horizontal ; end lobe exserted, dilated, its 

 notch linear. Cytioderm minutely punctate; transverse view 

 very near the two preceding. 



Diameter 15 -50 //. 



Pennsylvania and New Jersey, to Georgia. 



E. dbnIfobme, Wolle. Plate LI I, figs. 11, 12. 



('ells about one-third longer than broad; semicells urn- 

 shaped, three lobed; terminal lobe dilated, centrally sinuate; 

 lateral lobe- horizontal with .-ides converging, -innate, basal 

 portion protruding, emarginate, upper part broadly rounded, 

 a rounded sinus between them and the end lobe; protuber- 

 ance-, one at each angle of the terminal lobe ; one at each of 



the basal angles, two inter] bate, and one between the end 



and the lateral lobe-. 



Diameter 50 (l. ; length 5560 //. 

 Wood Lake, Passaic County, N. J. 



This form is nearest E. pectinatum, Breb., but differs in 

 most essential points. 



E. VERRUCOSUM, (Ehrb.) Ralfs. Plate XXVI, figs. 1, 5. 



( 'ells somewhat longer than broad; rough with conic gran- 

 ules; terminal lobe cuneate, no incision, but a broad shallow 

 sinus; lateral lobes cuneate with ends more or less concave ; 

 semicells with one large central inflation, and a -mallei- one on 

 each side ; two on the end lobe. 



Diameter about 75 />.., for larger typical form. 



