mew Species of Eolit. . 187 
band, and has frequently oné on the middle and one on 
the superior portion. 
Some of the varieties of this. shell, when undistorted, 
have so great an external resemblance to some of the 
varieties of "'unso pallidtus, Say, that a ge of one 
might answer, very well for both. 
It was found in abundance on the sad at the rapids, 
about a mile above the little falls of the River Potomac, 
apparently delighting in situations where one would 
imagine it difficult for it to adhere. "The only shells 
found in company with it were MErawia Virginica, 
Say, and AxcuLorUs nigréscens, Conrad, which latter 
was in great abundance and variety of form. Some of 
its less angular varieties closely approached A. dentátus, 
in their general appearance, but were easily distin- 
guished by the form of the, Aie A and the absence of 
the columellar lacuna. - 
. Eoris DIVERSA. 
Plate IV. fig. 0.1 
eorpore limaciforme, posticé acuto, diaphano, luteo-rufescente, 
digite distincto, sub-orbiculato, depresso; tentaculis gracilibus ue 
gatis duabus instructo, duobusque brevioribus ad partem posticum ca- 
pitis positis; branchi# aurantiace seriebus binis lateribus dorsi ‘dis- 
positis. Orificia generationis magna, pae collum ad latus nes 
ano paulum pone, péde uis laciniato. 
o rig Body limaciform, very ES elon- 
gated, tapering to a fine point and very contractile, 
semi-transparent, of a very pale yellow, to which a 
tinge of. red is imparted by the viscera showing through ; 
head very distinct, sub-orbicular, depressed, ENS 
we o two long, slender, lateral tentacula, arising from 
