EUASTBUM. Ill 



its notch linear. Cytioderm minutely punctate ; transverse- 

 rie^ very near the two preceding. 

 Diameter 45-50 jn. 



Pennsylvania and New Jersey, to Georgia. 



E. UENAFOKMB, WoUe. Plate LXIII, figs. 11, 12. 



Cells about one-third longer than broad ; semi-cells urn- 

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

 lateral lobes horizontal with sides converging, sinuate, basal 

 portion protruding, emarginate, upper part broadly rounded, 

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

 ances, one at each angle of the terminal lobe ; one at each 

 of the basal angles, two intermediate, and one between the 

 end and the lateral lobes. 



Diameter 50 yu. ; length 55-60 ju. 



Wood Lake, Passaic County, N. J. 



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

 most essential points. 



E. VEEEUCOSTJM, ( Bhrb. ), Ealfs. Plate XXX, figs. 1, 5. 



Cells somewhat longer than broad ; rough with conical 

 granules ; terminal lobe cuneate, no incision, but a broad, 

 shallow sinus ; lateral lobes cuneate with ends more or less 

 concave ; semi-cells with one large central infiation, and a 

 smaller one on each side ; two on the end lobe. 



Diameter about 75 yu., for larger typical form. 



Var. SIMPLEX, Joshua. Jour. Bet., Feb., 1885. Plate XLII, 

 figs. 12, 13. 

 Of stout habit, terminal lobe very short and with shallow 

 incision ; central infiation either none or very small ; no 

 other. It is nearest to the Cosmarium in Eeinsch's contribu- 

 tion. Plate XVI, tig. 9, the verrucae are perhaps some- 

 what larger than in the typical plant. 

 Diameter 65 jli. ; length 85 ju. 

 Canada. 



The following varieties deserve a separate note : 

 Var. Ceux Aericanum, WoUe. Plate XXX, fig. 2. 



The more angular, and more distended lobes, give this 

 form a stronger resemblance to an African Micrasterias, de- 

 scribed by Cohn, and suggests the name. 

 Pond, eastern Pennsylvania. 



Var. ALATUM, Wolle. Plate XXX, fig. 4. Very near Corda's 

 Cosmarium alatum. 



Marsh pools near Minneapolis, Minn., and Bucks Co., Pa. 



