HELIX §. 76. 
409 
Helix polygyrata Bimi, in Bost. jouni. III. p. 391. t. 19. f. 4. 
Polygyra septemvolva Say in Plulad, journ. I. P. 2. 18*8. p. 278.*) 
— — Sow. Conch. Man. ed. II. p. 234. f. 275. 276? 
— planorbula BecJc ind. p. 23. 
Habitat in America boreali: Georgia, Florida. 
^^1064. H. volvosds Parreyss, 
T. umbilicata, orbicuiato-convexa, tenuis, rufo-cornea, pel- 
lucida, regulariter costulato-striata; spira brevissima , convexa; 
anfr. 7 convexi, regulariter accrescentes, ultimus reliquis superne 
vix latior, angulatus, infra angulum inflatus, striatus, nitidus; 
umbilicus latus, regularis, anfractu ultimo latissimo, reliquis re- 
gulariter decrescentibus; apertura majuscula, reniformis; perist. 
intus callosum, reflexum, marginibus callo brevi, triangulari, den- 
tiformi junctis. — Diam. maj. 9, min. 8, olt. 4 mill. (Coli. Nr. 644.) 
Helix volvoxis Parr. in sched. 
— — Pfr. Symb. 111. p. 80. 
— — Chemn. ed. II. Helix N. 393. t. 66. f. 4 — 6.^ 
Polygyra septemvolva Beck ind. p. 23? 
Habitat in America boreali: Georgia, Florida. 
Obs. Hanc speciem, a praecedente loto coelo diversam, saepius ex Ame- 
rica nomine II. seplemvolvae Say accepimus. 
1065. H. microdonta Deshayes. 
T. umbilicata, orbiculato-plana, cornea vel pallide rufescens, 
superne plana , oblique et argute striata, subtus convexa, tener- 
rime striata, nitida, maculis opacis radiantibus notata, umbilico 
infundibuliformi excavata; anfr. 6, ultimus ad aperturam gibbus; 
apertura subtriaugularis; perist. subincrassatum, reflexiusculum, 
marginibus dente calloso, triangulari junctis. — Diam. maj. 9, 
min. 8, ait. 3'/a mill. (Coli. Nr. 645.) 
Helix microdonta Desh. in Fer. List. p. 6. t. 72. f. 13.**) 
— — Chemn. ed. II. Ilelix N. 395. t. 66. f. 10 — 12. 
— plana Dunker in Phil. Icon. L 3. p. 51. t. 3. f. 1 1. 
Habitat in insulis Bennudis ct in Texas (teste coli. Menkeana). 
Obs. Differt a sequente spira plana, anfractibus subtus magis evolutis, 
minus inflatis, umbilico exlus dilatato, perist. subincrassato , dente majore pa- 
rietis aperluralis. 
*) Verba descriptionis Sayanae: «bonoaili Ihe four e.xterior volulions 
equally prominent, transverse diamolers equal lo tliose of the npper surface; 
umbilicus Central, moderate, attenuated to tho apex so as to exhibit the remain- 
ing volutions», ad speciens nostram non omnino cpiadrant. 
**) T. discoidea, planulata , albo-grisea, flammulis obliquis fuscis subru- 
bescentibusve ornata; superne spira depressissima, subtus profunde lateque 
in ambitu umbilicata , tenuissime et regulariter striata; apertura obliqua, mar- 
ginata. ovato-semilunari; labro dente obliquo, minimo praedito. (Desh. 1. c.) 
