Key to the terrestrial gastropod genera of Wisconsin and nearby states
Adult Shells only!

1a. Individuals without external shell 1b. Individuals with external shell

2a. Shell as wide or wider than tall 2b. Shell taller than wide

3a. Shell approximately as wide (.8-1.2x) as tall 3b. Shell obviously wider (>1.2x) than tall

4a. Shell umbilicate 4b. Shell imperforate to rimate

5a. Shell >10mm diameter 5b. Shell <10mm diameter

6a. Shell imperforate, peristome white, expanded 6b. Shell narrowly umbilicate or rimate, peristome thin

7a. Peristome thickened, shell surface dull, suture absent, shell >3 mm diameter 7b. Peristome thin, shell surface satiny to glossy, suture deep, shell <3mm diameter

8a. Shell diameter >6mm 8b. Shell diameter <6mm

9a. Shell with open umbilicus 9b. Shell performate, imperforate or rimate

10a. Peristome expanded, usually white 10b. Peristome thin

11a. Shell diameter >16mm 11b. Shell diameter <16mm

12a. Parietal and peg-shaped basal lamella present 12b. Parietal lamella absent, basal lamella a low ridge

13a. Peristome continuous, 'y' or 'u' shaped on parietal surface 13b. Peristome not continuous

14a. Basal and palatial lamellae present, umbilicus >2½ mm diameter 14b. Basal and palatial lamellae absent, umbilicus <2½ mm diameter

15a. Shell white, umbilicus >5mm wide 15b. Shell yellow to brown, umbilicus < 5mm wide

16a. Shell with spiral or transverse color markings 16b. Shell of single color

17a. Umbilicus, on average, <=1/5 shell diameter 17b. Umbilicus, on average, >1/5 shell diameter

18a. Shell >16mm diameter 18b. Shell <16mm diameter

19a. Umbilicus <1mm diameter 19b. Umbilicus >1mm diameter

20a. Umbilicus >1/3 shell diameter; shell surface dull, strongly ribbed 20b. Umbilicus <¼ shell diameter; shell surface shiny with indistinct ribs

21a. Shell diameter <7 mm 21b. Shell diameter >7 mm

22a. Peristome thin 22b. Peristome expanded, white

23a. Lamellae present on aperture base 23b. Lamellae absent within aperture

24a. Shell surface smooth 24b. Shell surface with thick, regularly-spaced ridges

25a. Whorl size increasing by at least 50% each revolution 25b. Whorl size increasing slowly in size, tighly coiled

26a. Shell rimate to umbilicate 26b. Shell imperforate

27a. Parietal lamella, if present, weak 27b. Strong parietal lamella present

28a. Basal and outer aperatural surface without lamellae, peristome not continuous above parietial lamellae 28b. Lamellae present on outer and basal aperatural surface

29a. Shell <10mm diameter, umbilicus <1mm diameter 29b. Shell >10mm diameter, umbilicus >2mm diameter

30a. Palatal lamellae absent 30b. Palatal lamellae present

31a. Shell <13mm diameter, long parietal lamella extending most of aperture length 31b. Shell >15mm diameter, parietal lamella (if present) much shorter than aperture

32a. Shell at least twice as wide as tall 32b. Shell less than twice as wide as tall

33a. Basal lamella a long ridge 33b. Basal lamella short, peg-like

34a. Shell imperforate 34b. Shell perforate to umbilicate

35a. Aperture wider than rest of shell, shell glassy, transparent 35b. Aperture less wide than rest of shell, shell transluscent to opaque

36a. Shell <2mm diameter 36b. Shell >2mm diameter

37a. Umbilicus <¼ diameter of shell 37b. Umbilicus >¼ diameter of shell

38a. Peristome expanded, white 38b. Peristome thin

39a. Aperture strongly crescent-shaped, its width remaining approximately the same throughout 39b. Aperture oval, its width being much greater in the middle

40a. Top of shell with thick elevated ribs 40b. Top of shell with low, indented ribs

41a. Adult shells with 4-6 whorls which increase less than twice in width per revolution 41b. Adult shells with <4 whorls which increase twice or more in width per revolution

42a. Upper shell surface with dull luster and strong ribs 42b. Upper shell surface shiny and with weak ribs

43a. Last 1/5 of body whorl whitened from thickened shell; lamellae present in aperture 43b. Body whorl neither thickened nor whitened; lamellae absent

44a. Shell surface with regular, widely spaced, indented ribs 44b. Shell surface with irregular, closely spaced ribs

45a. Shell surface without faint spiral lines 45b. Shell surface with faint spiral lines

46a. Shell 2½-3½mm diameter; milky-white 46b. Shell 4½-5½mm diameter; rusty-brown

47a. Adult shell diameter >3mm 47b. Adult shell diameter <3mm

48a. Peristome white, expanded 48b. Peristome thin

49a. Shell with prominent, raised spiral lines 49b. Shell without prominent, raised spiral lines

50a. Ribs small, approximately 10 per mm; shell color light yellow-brown 50b. Ribs large, approximately 5 per mm; shell color deep rusty-brown

51a. Peristome flared and usually thickened 51b. Peristome unflared and always unthickened

52a. Spiral lines present on protoconch 52b. Spiral lines not present on protoconch

53a. Whorl width increasing by at least 1.5x each revolution 53b. Whorl width increasing by less than 1.5x each revolution

54a. Ribs with distinct, sharp edges 54b. Ribs (if present) with indistinct, rounded edges

55a. Ribs not continuous, with regular pieces removed so that ribs look like a string of beads under high magnification; whorls increasing by at least 1.5 x per revolution 55b. Ribs continuous, whorls increasing by less than 1.5x per revolution

56a. Major ribs +/- 0.2mm tall, shell almost flat on top 56b. Major ribs (if any) <0.2mm tall, shell with clear dome

57a. Shell with domed spire; whorl base rounded; shell surface wrinkled 57b. Shell with flat spire; whorl base flattened; shell surface smooth

58a. Lax spiral with no more than 3 whorls in mature shell 58b. Tighter spiral with 4+ whorls in mature shell

59a. Aperture taking up ½ of shell 59b. Aperture taking up more than ½ of shell

60a. Shell and aperture broadly ovate 60b. Shell and aperture narrowly ovate to elongate

61a. Adult shell >4mm tall 61b. Adult shell <4mm tall

62a. Shell with glassy luster, transparent to transluscent, yellow to brown color 62b. Shell with silky to dull luster, opaque

63a. Peristome thickened or flared, white 63b. Peristome unthickened and unflared

64a. Lamellae present in aperture; shell white 64b. Lamellae absent in aperture; shell brown

65a. Shell <9mm tall, dark olive-brown color 65b. Shell >15mm tall, light gray-brown to white color

66a. Shell 1¼-1½ times taller than wide, with prominent 0.2mm elevated ribs 66b. Shell >1½ times taller than wide, ribs (if present) much less than 0.2mm tall

67a. Shell at least 2½ times taller than wide, shell white 67b. Shell 1½-2½ times taller than wide

68a. 0-2 lamellae present in aperture 68b. 3+ lamellae present in apreature

69a. Shell white 69b. Shell brown

70a. Shell >3mm tall 70b. Shell <3mm tall

71a. Shell brown, sinulus usually strong 71b. Shell white to clear, sinulus absent