19G HELICID^E. 



of Polygra Dorfeuillana and Troostiana, the opinion 

 which I derived from his descriptions and figures has 

 been confirmed, and I cannot doubt the specific identity 

 of the three. There is, however, much difficulty in iden- 

 tifying specimens of Mr. Say's Polygyrce : they vary 

 much in size, at maturity ; and the younger shells differ 

 from the older, in a remarkable manner, in the character 

 of the aperture. 



The original specific name, plicata, being preoccupied 

 in this genus, I have adopted Mr. Say's second name, 

 fatigiata. 



44. HELIX SEPTEMVOLVA, SAY. 

 PLATE XXXVIII. XXXIX. FIGURE 1. 



H. testa orbicular!, discoidea, umbilicata, cornea ; an- 

 fractibus numerosis, oblique et acute striatis ; apertura ab 

 axe remota, sub-orbiculari, marginibus connexis ; columella 

 unilamellata ; labro albido, margine reflexo. 



SYNONYMS AND REFERENCES. 



Helix septemvolva, SAY, Journ. Acad. I. 278, anno 1818. 

 Kich. Encyc. IV. 



BINNEY, Boston Journ. Nat. Hist. III. 391, pi. 19, f. 4. 



FERUSSAC, Tab. Syst. 38 ; Hist. pi. 51 B. f. 6. 



WOOD, Index, Sup. pi. 7, f. 14. 



DESHAYES, in Ferussac, Coniiu. 5. 



SOWERBY, Conch. Manual, 2d. ed. f. 275. 

 Helix planorbula, LAMARCK, VI. 89. 



DESHAYES, Encyc. Meth. II. 208 ; in Lamarck, VIII. 67. 



DELESSERT, Recueil, lab. 26, f. 3. 

 Helix cereolus, PFELFFER, Monog. Helic. Viv. I. 408. 



DESCRIPTION. 



AXIMAL brownish, tentacles darker, very long and 



