GASTROPODA 525 



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

 and dark colored, with 4V2 whorls and with a deep umbilicus; height 13 

 mm.; diameter 26 mm.: eastern and central 



2. VlTRiNA Draparnaud. Shell small, C'-i'^^dw- -^ /^"^ 



not entirely enclosing the animal, with a ^--' — ''' 



low spire, thin and shining, and 2 to 3 ^^s- 813 Fig. 814 



whorls, the last large, with a large aperture Fig. 813 — Omphalina fuUgi- 

 ^ . . . • . nosa (Baker). Fig. 814 — Vit- 



and a thin lip: cosmopolitan; 100 species, 3 rina Umpida (Binney). 



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. VlTEEA Fitzinger. Shell thin, smooth, and shining, depressed 



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

 species. 



V. hanmionis (Strcim) (Fig. 815). Shell with a nar- 

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

 '.'^^:.J wide: entire country, south to South Carolina; common; 



Europe. 



^vure^a V. indentata (Say). Shell highly polished, without 



^BhSeyK umbilicus, but with umbilical region indented; 2.5 mm. 

 high and 5 mm. wide: entire country. 



4. EucoNULUS 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. Muller) (Fig. 816). Sheir smooth and shining, 

 light 3'ellowish 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 ^^conuiua 

 species. (Walker). 



Key to the species of Zonitoides here described: 



Oi Surface of shell smooth. 



6i Diameter 7.5 mm Z. nitida 



63 Diameter 5 mm Z. arbobea 



a. Surface striated or ribbed ; shell minute. 



61 Surface striated Z- minuscula 



6a Surface folded and reticulated Z. milium 



Z. nitida (0. F. Miiller). 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. 



