25ii APPENDIX. 



C. CLASS MOLLUSCA. 



The shells described in the following pages constitute 

 but a small portion of the collection obtained during the 

 expedition. Those collected on St. Peter's river were 

 packed in a box, and intrusted to the men who returned in 

 canoes to Fort St. Anthony ; this box has not j^et been re- 

 ceived, and is supposed to be lost. On the subsequent part 

 of the route I put all the univalves collected, iu a canteen 

 which I constantly carried, but which was finally lost at 

 Mackinaw. Another parcel of shells sent from Chicago has 

 not since been heard of. To this statement of our losses 

 I may add a still more important one, consisting of a box 

 which contained skins of quadrupeds, birds, reptiles, and 

 fishes. 



HELIX. 



1. H. harpa. 6'Ae// conic, reddish-brown ; ivhorls (oiiv, 

 convex, with numerous elevated, subequidistant, equal, 

 lameliform, acute lines across, the interstitial spaces flat and 

 vv^rinkled; aperture snhorhicuhr, truncated by the penul- 

 timate whorl, and very little oblique; lahruni simple; 

 umbilicus small, nearly concealed by the base of the la- 

 brum. 



Length rather more than one-tenth of an inch. 



Inhabits the North-west Territory. 



The elevated lines on this shell give it a very handsome 

 appearance, and readily distinguish it from any of our na- 

 tive species that I have seen. The European analogue is 

 the aculeata of MuUer, but our shell is destitute of re- 

 curved points on the lameliform lines. PI. 15, fig. 1. 



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