168 UNIVALVE SHELLS 



aperture, acute, two or three terminal whirls vitre- 

 ous; body whirl very little dilated : aperture rather 

 narrow : labrum with a pale margin, and dusky red 

 or blackish sub-margin. 



Inhabits Lakes Erie and Superior. 



Total length, 13-10 — of the aperture 11-20 of an 

 inch. 



This shell is remarkable for its narrow and elon- 

 gated form, and for the consequent, very oblique re- 

 volution of its whirls. V hen viewed in profile, it 

 has a slightly reflected appearance. It was kindly 

 sent to me for examination by my friends Messrs. S. 

 B. Collins andD. H. Barnes of New York, and was 

 found in Lake Superior by Mr. Schoolcraft. I re- 

 collect to have seen a specimen two or three years 

 since brought from Lake Erie, by James Griffiths. 

 It is proportionally longer than elongatus. 



4. L. *appressus. Shell elongated ventricose ; volu- 

 tions six ; spire regularly attenuated to an acute tip, 

 rather shorter than the aperture; body whirl dilated, 

 proportionally large; aperture ample; columella 

 with the sinus of the fold profound , callus perfectly 

 appressed upon the shell, to the base. 



Inhabits Lake Superior. 



This shell exhibits very much the appearance of 

 L. stagnalis, but its body whirl is less proportionally 

 dilated. The callus of the labium is perfectly ap- 

 pressed to the surface of the whorl even to the base, 

 exactly as in stagnalis. I have seen but a single 

 weathered and broken specimen, which was sent me 



