326 New Fresh- Water Shells. 
the shell, conic, sub-acute at the apex, angle of its 
opposite sides about 65°; body-whorl inflated, sub- 
globular; aperture ovate, its plane, also the line of 
its length, at angles of about 15? with the axis of the 
shell, three-fifths as long as the shell; labrum thin, 
inner margin dark brown, inner sub-margin thickened 
with a light pink deposit ; columella strong, reflect- 
ed and spread over an umbilicus, which is rather 
large but not profound, and formed chiefly by the re- 
flection of the columella ; fold of the latter inconspic- 
uous. | 
Length, .28 inch; breadth, .17 inch. 
Cabinets of Bost. Soc. Nat. Hist.; of Middlebury 
College ; of Mr. Shiverick ; and my own. 
Habitat. New Bedford. 
Remarks. For this species I am indebted to Mr. 
Shiverick, who obtained numerous specimens. It re- 
sembles L. caperatus, Say; but in Say’s species the 
aperture is but one half the length, the revolving 
lines are raised, more distinct, and numerous, the 
umbilicus is rather less, and there is one more whorl. 
PLANORBIS VIRENS. 
Plate III. Fig. 15. 
P. testà parva, viridi, striis transversis crebris, volventibus tenuissi- 
mis; anfractibus quatuor; spirà haud prominente, vix concava ; an- 
fractu ultimo magno, superné subplanulato, inferné subcarinato ; 
apertura suborbiculari; labro superné prominente; umbilico sublato, 
profundo. 
Shell small, greenish horn color, with thick, obvi- 
ous strie of growth, and very slight revolving lines, 
with a green, rough epidermis; whorls four; suture 
impressed ; spire not rising above the last whorl, but 
