170 UNIVALVE SHELLS 



bium, calcareous deposit copious, not perfectly ap- 

 pressed at base, but leaving a very small umbilical 

 aperture. 



Inhabits Cayuga Lake. 



Length 7-20 of an inch. 



Found by Mr. Augustus Jessup. It is closely 

 allied to L. elodes, but the whirls are more convex, 

 one less in number, and the two terminal ones are 

 proportionally smaller; the callus of the labium, 

 also, near its inferior termination, is applied still 

 more closely to the surface of the body whirl. 



7. L. *macrostomus. Shell sub-oval ; whirls five, 

 body whirl somewhat reticulated; suture not pro- 

 foundly indented; spire about two-thirds of the 

 length of the aperture, acute ; aperture much dilated ; 

 labrum not thickened on the inner sub-margin. 



Inhabits Cayuga Lake. 



Length one half of an inch, and upwards. 



Imperfect specimens of this shell were found on 

 the shore of Cayuga Lake by Mr. A. Jessup, but they 

 are sufficiently entire, to exhibit considerable similari- 

 ty to some varieties of L. auricularius of Europe. 

 It may readily be distinguished from L.catascopium, 

 by its much more dilated aperture. 



8. L. *emarginatus. Shell rather thin, translu- 

 cent ; volutions four, very convex ; body whirl large; 

 suture deeply impressed; spire somewhat eroded; 

 mouth two- thirds of the length of the shell. 



Length nearly 4-5 of an inch ; of the mouth half 

 inch. 



