104 HELIX §. 20. 
distantibus. — Diam. maj. 8, min, TVs, ait. vix 3 mill. (Coli. 
Nr. 137.) 
Helix perspectiva Say in Philad. journ. I. 1 8 17. p. 18. 
— — (Helicella) F^j\ pr. 198. Hist. t 86. f. 1. 
— — Lam. cd. Dli. 213. p. 130. 
— — Binn. in Bost. journ. III. p. 430. (. 21. f. 4. 
— — Chemn. ed. II. Helix N. 534. t. 85. f. 30 — 32. 
— patula Desh. in Encycl. m^th. II. N. 27. 
Em^yomphala perspectiva Beck ind. p. 9. 
Patula perspectiva Helcl in Isis 1837. p. 916. 
Habitat in America boreali, prope lacum Erie. 
^ 2G2. H. striatella Anthony. 
T. umbilicata, orbiculato-convexiuscula , tenuissima, fusco- 
cornea, confcrtim costulata; anfr. 4 vix convexiusculi, ultimus 
basi inflatus, latiusculus; umbilicus majusculus, pervius; apertura 
subcircularis ; perist. simplex, acutura, marginilms approximalis. 
— Diam. maj. 6, min. 5 '/ 2 , ait. 3 mill. (Coli. Nr. 138.) 
Helix striatella Anth. in Bost. journ. ID. p. 278. t. 3. 
— — Binil. in Bost; journ. III. p. 432. ^ 
— — Gow/cZ report p. 178. f. 112. 
— — Chemn, ed. II. HelLx N. 535. t. 85. f. 36 — 38. 
— perspectiva Fer. hist. t. 79. f. 7. 
Habitat in America boreali: Ohio, Massachusetts , Vermont. 
Ohs. Differt ab H. perspectiva losla minore, convexiore, anfi*actibus ma- 
gis inaequalibus, umbilico angustiore et apertura subcirculari. An nihilominus 
ejus varietas minor? 
263. H. Belcheri PIV*. 
T. late umbilicata, depressa, tenuis, diaphana, superne con- 
fertim costulato- striata, subtus sublaevigata , nitida, concolor 
corneo-ccrea ; spira vix convexa; anfr. 5 vix convexiusculi , ulti- 
mus basi subplanulatus; apertura obliqua, lunalo-ovalis; perist. 
simplex, acutum. — Diam. maj. 873, min. 7, ait. 4 mill, (Mus. 
Cuming.) 
Helix Belcheri Pfr. in Proc. Zool, Soc. 1845. p. 128. 
Habitat . . . ? (Ex itinere Belcheri.) 
263^ H. gradata Gould, •f 
T. parva, planorboidea, tenuis, nitida, rufo^ridis, luteo ra- 
dialiin variegata, supra depressa, infra acctabuliforrais ; spirae 
anfr. 5 convexi, intra umbilicum angulati, oblique et confcrtim 
striati, striis interruptis volventibus decussati, ultimus subangu- 
latus, versus aperturam deflexus; sutura canaliculata; apertura 
