GASTROPODA 



519 



S. retusa Lea (S. ovalis Gould). Shell ovate, with 3 whorls, light 

 yellowish or grayish and shining and minutely striate ; spire short ; aper- 

 ture long and narrow ; length 19 mm. ; width 7 mm. : eastern and central 

 states. 



S. avara Say (Fig. 799). Shell elongate, 

 with a long spire, yellowish, rosy, or greenish ; 

 whorls 3; suture very deep; length 11 mm.; 

 width 4.5 mm. : North America ; common ; often 

 under wet logs. 



Fig. 798 



Fig. 798 Succinea ovalis 

 (Binney). Fig. 799 Succi- 

 nea avara (Baker). 



FAMILY 6. HELICIDAE. 



Shell with a rather low conical spire and 

 consisting of 5 to 7 whorls; aperture either 

 simple or with teeth, and with a wide re- 

 flexed lip; teeth of radula bicuspid and tricuspid; ureter reflexed; foot 

 without marginal grooves : about 30 genera and several thousand species. 



Key to the genera of Helicidae here described: 



a t Dart sac, genital mucous glands, and flagellum present (Fig. 800) . .1. HELIX 

 a a Dart sac, genital mucous glands, and flagellum absent (Fig. 801) .2. POLYGYRA 



1. HELIX* L. Shell heliciform (Fig. 772) ; jaw with prominent 

 ribs; 1 or 2 dart sacs, genital mucous glands, and flagellum present 

 (Fig. 800), although these organs may be rudimentary: many hundred 



species in the Palearctic re- 

 gion; poorly represented in 

 America. 



H. aspersa 0. F. Muller 

 (Fig. 771). Shell yellowish 

 or grayish, with brown re- 

 volving bands of varying 

 widths; lowest whorl very 

 large; aperture large, round, 

 without teeth; height and di- 

 ameter 22 mm. : an European 

 species, which has been found 

 in Portland, Maine, Charles- 

 ton, S. C., and other places; 

 California. 



H. pomatia L. French snail. Edible snail. Shell rather thin, 5 

 cm. long and wide, yellowish-brown in color, often with several broad 

 revolving bands; aperture without teeth; narrow, deep umbilicus pres- 



Fig. 800 Portion of the genital organs of 

 Helix (Kingsley). 1, genital pore; 2, penis; 

 3, flagellum ; 4, proximal portion of sperm duct ; 

 5, proximal portion of oviduct ; 6, proximal 

 portion of spermatheca ; 7, mucous glands ; 8, 

 dart sac. 



* See "Land and Fresh Water Mollusks of Yucatan and Mexico," by H. A. Pilsbry, 

 Proc. Acad. Nat. Sci., Phila., 1891, p. 313. 



