IIELIX §. 76. 409 



Ilelix polygyrala Binn. in Bost joiui). III. p. 391. t. 19. f. 4. 

 Polygyra scptemvolva Say m Philad. journ. I. P. 2. 1818. p. 278.*) 



— — Soiv. Conch. Man. cd. 11. p. 234. f. 275. 276? 



— planorbula Beck ind. p. 23. 

 Habitat in America boreali : Georgia , Florida. 



1064. H. volvox.is Parreyss. 



T. umbilicata, orbiculato-convexa, tenuis, rufo-cornea, pel- 

 lucida, regulariter costulato-striata ; spira brevissinia, 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- 

 liformi junctis. — Diam. maj. 9, min. 8, alt. 4 miU. (Cofl. Nr. 644.) 

 Helix volvoxis Parr. in sched. 



— - Pfr. Symb. III. 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. 



b s. Hanc speciem, a praecedente tolo coelo diversam , saepius ex Anie- 

 rica nomine H. septemvolvae 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 subtriangularis; perist. subincrassatum , reflexiusculum, 

 marginibus dente calloso , triangulari junctis. — Diam. maj. 9, 

 min. 8, alt. sy^ mill. (GoII. Nr. 645.) 



Helix microdonta Desh. in Fer. hist. p. 6. t. 72. f. 13.**) 



— — Chemn. ed. U. Helix N. 395. t. 66. f. 10 — 12. 



— plana Dunker in Phil. Icon. I. 3. p. 51. t. 3. f. 11. 



Habitat in insulis Bermudis et in Texas (teste coll. Menkeana). 



Obs. Differt a sequente spira plana, anfraclibus subtus magis evolutis, 

 rainus inflatis, umbiiico extus dilatato, perist. subincrassato , dente majore pa- 

 rietis aperturalis. 



*) Verba descriplionis Sayanae: «beneath the four exterior volutions 

 equally prominent , transverse diameters equal to tbose of the upper surface; 

 umbiUcus central, moderate, attenuated to the apex so as to exhibit the remain- 

 ing volutions», ad speciera nostrara non omnino quadrant. 



**) T. discoidea , planulata , albo-grisea , flammuhs obhquis fuscis subru- 

 bescentibusve ornala; superne spira depressissima , subtus profunde lateque 

 in ambitu umbiiicata , tenuissime et regulariter striata ; apertura obliqua , mar- 

 ginala, ovato-semihuiari ; labro dcnte obhquo , minimo praedito. (Dcsh. 1. c.) 



