20 [May, 1841. 



3. U. paralellus. Oblong 1 , sub-rhomboidal, convex, moderately 



thick, slightly contracted from beak to base ; hinge and basal 



margins parallel, nearly rectilinear; posterior margin oblique; 



extremity obtusely rounded; epidermis dark olive-brown; 



within white; cardinal teeth oblique, double in each valve ; 



cardinal area under the beaks almost obliterated. (Length 



3.7; height 1.1; diameter 1.8.) 



Some' conchologists may consider this to be a variety of U. 

 purpureus, (Say,) and as but one specimen has been received, I 

 cannot judge of the amount of difference which will obtain be- 

 tween the two species. I think the purpureus has never yet 

 been found nearly so far south-west as Louisiana; certainly, 

 after a long examination of the waters of Alabama, I was unable 

 to find it. The paralellus differs from purpureus in having a 

 white interior, in the obliteration of the cardinal area, in the regular 

 convexity of the valves, and in having a much larger accessory 

 muscular impression. 



These three species are in the collection of the Academy: they 

 were sent from Jackson, in Louisiana. 



STATED MEETING, May 18, 1841. 

 Vice President Morton in the Chair. 



DONATIONS TO MUSEUM. 



Helix Blandingiana ; St. Johns, Liberia. Area senilis ; same 



locality. From Dr. Wm. Blanding. 

 Fossil Aspergillum, from the Newer Pliocene of Palermo, in 



Sicily : and Lutraria petrosa, (Conrad) from Vance's Ferry, 



S. Carolina. From Dr. Morton. 



