Height usually greater than width; surface silky; south-central states 

 Euconulus chersinus (Say) 



210. Umbilicus about one-seventh to one-eighth diameter of shell; tropical 



species 



Thysanophora plagiotycha (Shuttleworth) 

 Umbilicus smaller in proportion to shell 211. 



211. Shell definitely lengthwise ribbed; northern states 



Zoogenetes harpa (Say) 

 Shell striate; tropical species in Florida 

 Pupisoma minus Pilsbry 



212. Shell dull and opaque, or with a color pattern 213. 

 Shell glossy or translucent, plain colored 222. 



213. Umbilicus narrow or very small 214. 

 Umbilicus moderate to broad 215. 



214. Shell grayish, usually dark banded; about V2"; southern states 



Praticolella griseola (Pfeiffer) 

 Shell brownish (with a light band encircling the body whorl in one 

 species) 265. 



215. With about four whorls; color plain; umbilicus showing the volutions 



224. 

 With more whorls; with a color pattern in some species 216. 



216. Color usually pale; shell usually banded or keeled; western species 217. 

 Color chestnut brown; with or without color markings; more generally 



distributed 218. 



217. Lip slightly reflected in the lower columellar area; surface often slightly 



glossy; usually with a narrow, light-bordered, dark band; about Y/'; 

 southwestern species, centering around Tucson, Arizona (Many spc' 

 cies, of which a representative is given) 



Sonorella hachitana (Dall) Sonora Snail 

 Lip often continuing as a thin callus across the parietal wall; surface dull, 

 often banded or keeled; about 1"; western states (Many species, of 

 which a representative is given) 



Oreohelix strigosa (Gould) White Desert Snail 



218. No color markings; about 5/16" 219. 

 With color markings; usually larger 221. 



219. Body whorl transversely rib-striate; aperture without teeth 220. 

 Body whorl smooth or spirally ridged, or with the aperture constricted 



by a tooth or callus on the parietal wall 247. 



220. Umbilicus shallow; eastern and central states, except New England 



Discus patulus (Deshayes) Brown Leaf Snail 

 (Pyramidula perspectiva (Say) ) 

 Umbilicus deep, with nearly upright walls; northwestern states 

 Radiodiscus abietum (Baker) 



221. Shell dark banded; about 1" 



Angiuspira \ochi (Pfeitfcr) Banded Leaf Snail 

 (Pyramidula soUtaria (Say) ) 



138 



