T)psmulie(P.'] iNPusoniAL animat.cfles. 251 



jccting beyond the acute angles. Frond verj- minute. Terminal 

 notch broad. 



Var. /^i.y— Quadilatcral form ; truncate ends, with a small but 

 distinct notch at the centi-e. Length l-1968th to 1-1 106th. 



EtTASTRTm cuneatum. — Segments cuneate, not lobed ; terminal notch 

 not lineal'. Frond larger than that of any other species in tliis 

 section. Ends truncate. Length 1-20 8th. 



E. (?) sublobatum. — Segments sub-quadrate, somewhat conti'acted 

 beneath the end ; end margin sKghtly concave. Sides and end of 

 segments somewhat siuuated, and their base slightly inflated. This 

 species has close affinities with Cosmarium. Length 1 -523rd. 



E. cormitum (Kiitz.) — Segments three-lobed; terminal lobe cuneate, 

 included between two process-like projections of the basal portion. 



'E. pelta. (Corda.) — Segments quadrangular; end margin with a 

 rounded protuberance at each comer ; lateral margins with a small 

 protuberance at the basal end, and a larger one nearer the outer end. 



E. crenatum. (Kiitz.) maybe a variety of ^. elegans. 



E. crenulatum (Ehr.) — Small, corpuscles binate, elliptic, granular; 

 mai'gin with 8 to 12 crenatures. Size 1-1 150th. 



E. hinale (Ehr.) = Hetorocarpella hinalis (Turpin.) — Corpuscles 

 binate, sub-orbicular, distinctly tri-lobed on each side ; each of the 

 terminal lobes truncate ; the middle contiguous lobes rounded. 

 Diameter 1 -480th. Under the above name, both Ealfs and Ehren- 

 berg have described the Heterocarpella hinalis of Tui'pin ; yet the 

 descriptions would scarcely identify the same species, and the dif- 

 ference in size, as stated by the two natui-alists, is very considerable. 

 Ehrenberg's description is from a paper published in 1840. 



E. octohhim (Ehr.) — Corpuscles binate ; fi-ond oblong, plane, four 

 lobed on each side, the intermediate contiguous lobes bidentate at 

 the apex. Diameter 1-5 70th. 



E. (?) j3y^/rt«M?w = Frustulia cofecdformis. — Binate, very small, 

 elliptic, smooth, quite entire, imbedded in a gelatinous substance 

 with other specimens (social.) Diameter 1-1 750th. Maiine. 



Genus CosMARnrM:. — Corpuscles simple, constricted in the middle ; 

 segments as broad as, or broader than long ; neither sinuated nor 

 notched ; mostly Lnflato-compressed, but in some species orbicular, or 

 cylindrical. Ehrenberg united plants belonging to this genus with 

 others having lobed segments, in order to form his genus Euastrum 



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