AMNICOLA. 1 1 



Amnicola orhiculata, Lea, Tr. Am. Phil. Soc. IX, 16 ; Proc. II, 34. — Hal- 

 DEMAN, Mon. p. 24. 



Amnicola depressa, Teyon — Shell orbicular, sub- 

 hyaline ; whirls four, convex, the last large, equalling five- 

 sixths the length of the entire shell ; umbilicus narrow ; 

 aperture semicircular, labrum appressed within ; suture im- 

 pressed. Length and breadth four mill. (Fig. mag. 2J 

 times.) 



Hab. Mississippi River, at Davenport, Iowa ; Prof. Sheldon. 

 Coll. Acad. Nat. Sciences, and Smithsonian Institution. 

 Prof. D. S. Sheldon. Geo. W. Tryon, Jr. 



Shell subhyaline, rather solid, orbicular, with the spire depressed, con- 

 sisting of four whirls ; apex acute, suture profoundly impressed. Body 

 whirl very convex, equalling five-sixths the length of the shell, narrowly 

 umbilicate. Aperture semicircular, the inner lip being nearly straight. 

 The only shell which this resembles is Vivipara subglobosa, Say, which 

 differs in being double the size of A. depressa, with a rather more exserted 

 spire, and in having a more concave inner lip. {Tryon.) 



Amnicola depressa, Tkyon, Proc. Ac. N. Sc. Phila. Sept. 1862. Not yet 

 published. 



Spurious Species. 



Amnicola isogona, Lea, Tr. Am. Phil. Soc. IX, 16, is Leptoxis isogona. 

 Amnicola iniegra, Haldeman = Melania integra, Say, Vid. J. Ac. Nat. Sc. 



VIII. 200. 

 Amnicola seminalis, Cooper, Rep. on Minnesota, &c., p. 374, = Bithynia. 

 Amnicola nuttalliana, Cooper, Rep. on Minnesota, &c., p. 374,= 



The following are mentioned by name only in Wheatley's Cat. of U. S. 

 Shells. No description of them was ever published. 



Amnicola alhilahris, Ward, Ohio. I Amnicola Sayana, Lea, Ohio. 

 Amnicola dentata, Say, Florida. | Amnicola gibbosa, Anthony, Ohio. 



