324 Sketch of the Infusoria of the family Bacillaria. 



The small species (fig. 6) agrees pretty well with the above 

 characters. It is common in ponds near West Point. I have also 

 seen it in several American specimens of fossil infusoria. 



4, Gomphonema . (PL 3, fig. 7.) Frustules smooth, gemi- 

 nate or in fan-shaped groups, one side elongated, wedge-shaped, trun- 

 cate ; the other side obovate ; pedicel repeatedly dichotomous. Marine. 



I have examined this species only in a dry state, having first 

 noticed it on a glass slide on which I had preserved some speci- 

 mens of Echinella flabellata from Stonington, Conn. 



The figure is drawn from the dry specimens. 



Echinella, Ehr. 



Carapace simple, siliceous, fixed at one extremity to a pedicel, 

 wedgeformi, longer than broad, fan-shaped or verticillate by spon- 

 taneous division. 



1. Echinella faiellata. (PL 3, fig. 8.) Smooth, corpuscles linear, 

 cuneiform, truncate, slightly three-toothed, strise longitudinal, -^^ line 

 without the pedicel. Licmoplwra fiabellata, Ag. Greville in Hooker's 

 English Flora, V, p. 408. 



This beautiful marine production presents in its fan-shaped 

 groups of crystal-like corpuscles, an exceedingly elegant appear- 

 ance. The fans are supported by long flexible clavate pedicels, 

 which are grouped together in large bunches covering filamentous 

 marine Algae and zoophytes. 



I found it quite abundant at Stonington, Conn, in July. It is said 

 to occur also at Scotland, Venice, and at the Cape of Good Hope. 



2. Echinella . (PL 3, fig. 9.) Corpuscles smooth? lanceo- 

 late, truncate ; pedicel short, broadly clavate, often nearly circular, sup- 

 porting the radiating closely aggregated corpuscles. 



I detected this very elegant species about a year since in the 

 Hudson River near West Point, where it grows upon Potamoge- 

 ton, Enteromorpha, &c. It agrees in many respects with E. ful- 

 gens, Grev., but that is described as being striate, a character 

 which I have not perceived on our species. 



COCCONEMA. 



Carapace simple, bivalve or multivalve, siliceous, fixed by one 

 end, pediculate, longer than broad, pedicel in the direction of the 

 axis of the body. [Pedicellate Naviculce.) 



When separated from their footstalks, there is no good charac- 

 ter to distinguish them from Navicula, but the unsymmetrical 



