GASTROPODA 



525 



Fig. 813 



(23 



Fig. 814 



Fig. 813 Omphalina fuligi- 

 nosa (Baker). Fig. 814 Vit- 

 rina limpida (Binney). 



O. fuliginosa (Griffith) (Fig. 813). Shell depressed, thin, glossy, 

 and dark colored, with 4 1 /*> whorls and with a deep umbilicus; height 13 

 mm.; diameter 26 mm.: eastern and central 

 states. 



2. VITRINA Draparnaud. Shell small, 

 not entirely enclosing the animal, with a 

 low spire, thin and shining, and 2 to 3 

 whorls, the last large, with a large aperture 

 and a thin lip : cosmopolitan ; 100 species, 3 

 American, all northerly. 



V. limpida Gould (Fig. 814). Height 3 mm.; diameter 6 mm.: 

 western Pennsylvania, and to the west and north of it. 



3. VITEEA Fitzinger. Shell thin, smooth, and shining, depressed 



with 4 to 6 whorls; animal black dorsally: 21 American 

 species. 



V. hammonis (Strom) (Fig. 815). Shell with a nar- 

 row umbilicus, brownish in color; 2.5 mm. high and 5 mm. 

 wide: entire country, south to South Carolina; common; 

 Europe. 



V. indentata (Say). Shell highly polished, without 

 umbilicus, but with umbilical region indented; 2.5 mm. 

 high and 5 mm. wide: entire country. 



4. EUCONTTLTJS Reinhardt. Shell with 'a very narrow umbilicus 

 or with none, with rather high spire of 5 or 6 whorls : 3 American species. 



E. fulvus (0. F. Miiller) (Fig. 816). Shell smooth and shining, 

 light yellowish in color; 3 mm. high and 4 mm. in diame- 

 ter; color of animal black: circumpolar; entire country; 

 very common. 



5. ZONITOIDES Lehmann. Shell depressed, with wide 

 umbilicus, smooth or ribbed, shining; aperture large, 

 without teeth; long dart sac present: 15 American 

 species. 



Key to the species of Zonitoides here described: 



Oj Surface of shell smooth. 



bi Diameter 7.5 mm Z. NITIDA 



6, Diameter 5 mm Z. ARBOBEA 



a, Surface striated or ribbed ; shell minute. 



&! Surface striated Z. MINUSCULA 



6 a Surface folded and reticulated. Z. MILIUM 



Z. nitida (0. F. Muller). Shell elevated, with polished, yellowish 

 surface and 5 whorls; 3.6 mm. high and 7.5 mm. in diameter; animal 

 black: northern states and Canada; common on the banks of streams; 

 Europe. 



Fig. 816 

 Euconulus 



fulvus 

 (Walker). 



