Make your own free website on

Suborder Holopoda
Superfamily Polygyroidea

Four Families make up this Superfamily:

1.Polygyridae(North-America) 2.Corillidae(Far East,South-Africa) Genus Corilla Genus Sculptaria 3.Thysanopharidae(Tropical America's) Genus Mcleania Genus Microconus Genus Microphysula Genus Thysanophora 4.Ammonitellidae(Western USA) Genus Ammonitella Genus Polygyrella

The Polygyridae snails have medium sized,globose shells which are brown and sometimes toothed.There are about 260 species in 9 genera with 2 subfamilies.

Genus Allogona Genus Ashmunella Genus Cryptomastix Genus Mesodon Genus Neohelix Genus Polygyriscus Genus Praticolella Genus Stenotrema Genus Vespericola Genus Xolotrema Subfamily Polygyrinae Genus Polygyra Subfamily Triodopsinae Genus Triodopsis Polygyra auriculataSay,1818 Shell about 1.5 cm in diameter and 8 mm in height. In northern Florida to Tampa in the west.

Polygyra pustula Say,1821 Shell small,depressed with a convex spire,cinnamon-brown,with stiff brown hairs The parietal callus has a long tooth. Height 2.3-2.7 mm and width 4-4.7 mm In South-Carolina,Georgia,Florida and Alabama.

Polygyra pustuloides Bland,1858 Shell wide umbilicate,thin,pale horn colored Aperture oblique with a parietal tooth. Height 2.5 mm and width 5.5 mm with 5 whorls In South-Carolina,Georgia,Tennessee,Alabama,Florida and Mississippi

Polygyra leporina Gould,1848 Shell wide umbilicate,depressed,pale brown colored,with short hairs in younger snails Aperture with a tooth on the parietal callus Height 2.8-3.7 mm and width 5-6.5 mm with 4.6-5 whorls. In Tennessee,Alabama,Mississippi,Illinois,Indiana,Missouri,Arkansas,Louisiana,Oklahoma and Texas.

Polygyra triodontoides(Bland) Shell globose--depressed,thin, pale horn colored,smooth with a short spire Aperture round oval with two teeth. Height 4.9-6.5 mm and width 8.7-11 mm In MS,AR,OK,LA and TN.

Polygyra texasiana Moricand,1833 Shell perforate,strongly depressed,spire very low,pale brown to light buff colored often with a darker band above the periphery. The aperture has a two branched tooth on the parietal callus.. Height 5 mm and width 10-11 mm with 5.5 whorls. In AR,OK,LA and TN.

Polygyra plicata Say,1821 Shell perforate,depressed,spire slightly convex or flat,golden-brownish Aperture with a parietal tooth. Height 2.8-3.1 mm and width 5.5-7.7 mm with 5 whorls. In IN,KY,TN,AL and GA.

Polygyra jacksoni Bland,1866 Shell umbilicate,depressed,shiny,dark or pale horn in color. Aperture round oval with 3 teeth. Height 3.6-3.9 mm and wdth 6.3-8.2 mm with 6 whorls. In MS,Ar and OK.

Polygyra septemvolva Say,1818 The shell is about 7-15 mm in diameter and 3-4 mm in height. In grass in acid soil. Georgia,Florida to Texas.

Polygyra plana Dunker,1843 The shell is about 1 cm and light-brown. In Bermuda and the Western Bahama's.

Polygyra cereolus Mühlfeldt,1816 Shell disk-shaped,thin,yellowish to brown.Strongly marked with axial ridges. The aperture has a single tooth. Diameter 7-18 mm,height 4 mm. A very common species in southern Florida living on calcereous soil. There is a lot of difference in size in colonies. image:Bill Frank

Polygyrella polygyrella Bland & Cooper,1861 Shell discoidal with a pale greenish-yellow color,a little translucent and glossy. Height 3.7-5 mm and width 9.3-12.5 mm with 6.5-8 whorls. In Montana,Idaho,Washington and Oregon.

Stenotrema stenotrema Pfeiffer,1842 The shell is about 8-13 mm in diameter and 5-9 mm in height. The aperture has a long white or pinkish tooth. In Arkansas to Virginia and Ohio to Georgia.

Stenotrema hirsutum Say,1817 Shell pill shaped,9 mm in diameter and 6 mm in height,periostracum hairy. In woodlands in the Northeastern US(Canada and Maine to Georgia and west to Kansas)

Stenotrema magnifumosum Pilsbry,1900 Shell imperforate,spire convex,brown,aperture narrow with a parietal tooth. Basal lip is brown with a thin outer margin. Height 4.7-6.2 mm and width 6.4-9 mm with 5.25-5.5 whorls. In TN,NC and GA.

Stenotrema monodon Rackett,1821 Shell umbilicate,spire convex and low,whorls very closely coiled,a little translucent and glossy. Aperture round oval with a short white parietal tooth. Height 3.9-5.7 mm and width 6.7-9.4 mm with 5.75-6 whorls. In Ontario,PA,MD,OH,MS,IN,IL,WI,MN,IO,SD,NE,KS,MI.

Mesodon appressus(Say,1821) Shell about 19 mm in diameter and 9 mm in height,brownish with a closed umbilicus. The aperture has a long rounded parietal tooth. In Ohio to Virginia to Alabama,Bermuda.

Mesodon thyroides Say,1816 Shell about 17-28 mm in diameter and 11-18 mm in height,yellowish brown with a thick white lip. Ontario to Texas.

Mesodon chiloweensis Lewis,1870 The biggest Mesodon it reaches 40 mm in diameter and 24 mm in height. Umbilicus deep and large. Under leaves and debris in mountainous forests In Tennessee to western North-Carolina. photo:The Ohio State University:division of molluscs

Mesodon sayanus Pilsbry,1906 Similar to M.chiloweensis but smaller,25 mm in diameter and 15 mm in height. Shell glossy and yellowish with a narrow lip,usually with two teeth. In Canada to North-Carolina and west to Michigan on woody hills,in stone fences and under logs.

Mesodon clausus Say,1821 Shell about 1.5 cm. Ohio to Georgia to Alabama.

Mesodon mitchellianus Lea,1839 Shell about 1.7 cm with an closed umbilicus. New York to Ohio and Kentucky.

Mesodon pennsylvanicus Green,1827 Shell about 1.9 cm. In Western Pennsylvania to Missouri.

Mesodon elevatus Say,1821 Shell about 28 mm in diameter and 20 mm in height,with a large parietal tooth in the aperture. New York and Illinois to Mississipi and South-Carolina.

Mesodon rugeli Shuttleworth,1852 Shell 18 mm in diameter and 9 mm in height. Umbilicus covered and periostrcum bristly and fuzzy. In Virginia to Georgia and west to Kentucky and Alabama.

Mesodon zaletus Binney,1837 Shell 31 mm in diameter and up to 25 mm in height.Glossy and usual with a parietal tooth. Canada to North-Carolina and west to Wisconsin and Oklahoma. image courtesy of Larry Watrous

Neohelix dentifera Binney,1837 Shell about 2.4 cm,yellowish-brown with a thick white lip. In North-East USA in humid dead leaves.

Webbhelix multilineata Say,1821 Shell about 2.5 cm.

Triodopsis dentifera Binney,1837 Shell 28 mm in diameter and 16 mm in height,aperture with a parietal tooth. In Canada and Maine to North-Carolina

Triodopsis tridentata Say,1816 Shell about 20 mm in diameter and 11 mm in height,pale to dark buff,with three teeth in the aperture. In Canada and Maine to Georgia and west to Mississippi and Iowa.

Triodopsis hopetonensis Shuttleworth,1852 Shell about 13 mm in diameter and 6 mm in height . In Virginia to Florida and Alabama living on coastal plains,a common urban snail. North-Carolina to North-Florida and Alabama,close to brackish water.

Triodopsis juxtidens Pilsbry,1894 Shell 19 mm in diameter and 10 mm in height,with three teeth;the two lip teeth stand close together. In Vermont to Georgia.

Triodopsis fosteri Baker,1921 Shell diameter is 22 mm and height 11 mm.It has a blade-shaped lamella on the basal lip and a strong parietal tooth. In Alabama to Iowa,but also in New Jersey.

Triodopsis denotata Ferussac,1821 Shell 26 mm in diameter and 13 mm in height.The periostracum has short,stiff hairs. It has a blade-shaped lamella on the basal lip. In Canada and Vermont to georgia and west to Illinois and Arkansas.

Triodopsis fallax Say,1825 Shell umbilicate,depressed,with a dome-shaped spire,dark olive-brown.Closely coiled whorls. Aperture trilobed with a inwardly bent tooth and a long parietal tooth which is strongly angular curved. Height 7.5-8.2 mm and width 11.8-12.4 mm with 5.5 whorls. In PA,NJ,MD,WA,VA,NC,SC,TN,GA.

Triodopsis albolabris Say,1816 Shell depressed-globose,solid,cream buff to chamois colored. Height 16-18.7 mm and width 25.5-31 mm with 5-5.5 whorls. In Quebec,Ontario,United States:Maine to South-Georgia and west to the Mississppi river. Triodopsis obstricta Say,1821 Similar to T.denotata but it has a strong sharp keel along the periphery. In South-Carolina and Georgia west to Louisiana and Arkansas.

Allegona profunda Say,1821 Shell about 3 cm,in deep woods.

Allegona townsendiana Lea,1838 Shell about 2.5 cm. In Western-Oregon and Washington.

Ashmunella levettei Bland,1881 © 2003 William Leonard

Vespericola columbianus Lea,1838 © 2005 Kristiina Ovaska Distribution:British Columbia(Canada),Alaska,Washington,Oregon(USA).

Cryptomastix deviaGould,1846 Larger than C. mullani and has the thickest point of the swelling on the basal lip located closer to the columella than to the periphery. In British Columbia,Washington and Oregon © 2005 Kristiina Ovaska

Cryptomastix germana Gould,1851 Smaller than C.mullani.In British Columbia,Washington and Oregon. © 2005 Kristiina Ovaska

Cryptomastix mullani Bland & Cooper,1881 Shell:medium sized,depressed helicoid with a very low spire,surface glossy or matt,sutures deep, umbilicus small.Juveniles have minute hairs on the periostracum,these can still be present in adults but usually fall off. Aperture oval with a white parietal denticle,lip thick and white,strongly bend backward. Width to 16 mm with 4.75-5.5 whorls. Habitat:Near streams under rocks,logs and leaflitter from 500-1800m. Distribution:Southeast British Columbia; Washington east of the Cascade Mountains to northeast Oregon and east through Idaho to western Montana. © 2000 William Leonard

Images copyright 1902 by Dodd,Mead & company.

to main page