HELIX 55. 
291 
/?. Minor, cingulis distantibus 6 — 7 lateritiis: diam. maj. 18, min. 16, 
ait. 1 1 mill. (Spec.) * 
Helix muUilineata var. Chemii. 1. c. t. 71. f. 19. 20. 
Habitat in America boreali: Illinois et Missouri. 
y 759* H. pennsylvanica Green. 
T. obtecte perforata, subglobosa, tenuis, pellucida, luteo- 
cornea, subtiliter oblique cosluiata; anfr. 5 planiusculi, ultimus 
ad aperturam subconstrictus ; apertura lunaris; perist. late re- 
flexum, intus albo-labiatum , margine columellari subrecto, ex- 
panso, umbilicum obtegente. — Diam, maj, 17, min. 15, ait. 11 — 
12miU. (Coli. Nr. 463.) 
Helix perinsylvanica Green Contrib. to Maclurian Lyc. N. 1. p. 8. 
— — Binn. in Bost. journ. I. p. 483. t. 16. 
— — Pfr, Symb. II. p. 36. 
_ _ Chemn, ed. II. Helix N. 44'2.'t. 73. f. 4. 5. 
— clausa Say in Philad. journ. II. p. 154. Nec Rafin. 
— — Say Amer. Gonch. t. 37. f. 1. 
— — Binn* in Bost. journ. I. p. 482. t. 15. 
Tridopsis thyroidus var* edentula Bech ind. p.’ 23? 
Habitat in America boreali: Pennsylvania, Ohio, Illinois. 
Obs. BifTert ab H. muUilineata spira elatiore et lamina umbilicum obte- 
gente mullo minus expansa, ab H. thyroide umbilico omnino clauso, apertura 
edentula , elc. 
760. H. Mitchelliana Lea. 
T. superne obtuse conica, inferne inflafa, longitudinaliter et 
subtiliter striata, cornea, diaphana, imperforata; anfr. 5; aper- 
tura subrotundata; labrum subreflexum; columella .laevis. — 
Diam. 0,7, long. 0,4 poli. (Lea.) — Diam. maj. 19, ait. 12 mill. 
(ex ic.) — CoII. Nr. 464? 
Helix Mitchelliana Lea obs. II. p. 87. t. 23. f. 71. 
— — ? Chemn. ed. fl. Helix N. 332. t. 56. f. 6—8. 
Habitat in America boreali: Ohio. 
Obs. «Affinis clausae et jejunae Say. Striae majores, quam harum; labrum 
magis acutum, quam clausae». — Gonf. H. ihyroides Nr. 900. 
761. H. plicaria Lamarck. 
T. obtecte perforata, orbiculato-depressa, violacescenti-fusca, 
basi pallidior, oblique granulato-costata; anfr. 4ya convexi, ulti- 
mus antice valde deflexus; apertura subhorizontalis, angusta, 
subovalis, intus alba ; perist. acutum, angulatim latissime expan- 
sum, intus incrassatum, marginibus callo junctis. — Diam. maj. 
20, min..16, ait. 10 — 11 mill. (Coli. Nr. 465.) 
Helix plicaria Lam. Enc. meth. t. 462. f. 3. 
19 * 
