IIKl. IX. -Plate CXVI. 



Distinguished by the peculiar pinched dctlected forma, 

 lion of the lip-margins. 



Species 674. (Mus. Cuming.) 



Hki.ix Planobboides. Hel. testa late umbilicatd, de- 

 /jreud, auperni Ifpviuscitla, fjasi coHulato-striald, ilia- 

 pluina, corneo-Jlamdd ; tpird l/revissitiid ; mturd me- 

 diocri ; atifractiins quinque, planimculis, ultimo anlice 

 lion deflexo ; aperturd vie ohliqud, lunato-circulari ; 

 periilomate timplici, niarginibufs approximat'ui, iasali 

 rfjlexiusculo. 



The Pi,.\nohbis-like Helix. Shell broadly umbili- 

 cated, depnissed, rather smootli at the upper part, 

 finely rib-like striated at the base, diaphanous, horny- 

 yellow ; spire verj" short ; suture middling ; whorls 

 five, rather flat, the last not deflected in front ; aper- 

 ture scarcely oblique, lunar-circular; lip simple, with 

 the margins approximated, basal margin a little re- 

 flected. 



Ferl-ss.\c, Hist. Moll. pi. 82. f. 4. 



Mesomp/lix Planorboides, Rafinesque. 

 Helix concava, Say. 



Hoi. Illinois and Missouri, North .\merica. 



.V very delicate pale greenish-yellow shell, partaking of 

 the form of Planorhit and of Cyclottoma. 



Species 675. (Mus. Cuming.) 



Helix ei.lioi.nos.\. Hel. letld anyiuli umbilicatd, dt- 

 preJoS, tenui, tlrialuld, nilidd, olicaceo-cornn ; >pird 

 vii elecald ; an/racliiiu qualuor ad quimpte, planiu$- 

 culi), rapidi accrencentibun, uliuim magna, m/xlepreuo ; 

 aperturd perobliqud, ampld, lunato-ovali ; perUlomate 

 timplici, acuta, margine uiniilicaii reJlexiuAculo. 



TuE SOOTY Helix. Shell narrowly umbilicatcd, de- 

 pressed, thin, finely striated, shining, olive-honiy ; 

 spire but little raised ; whorls four to five, rather flat, 

 increasin;^ rapidly, the last large, a little depn-ssed ; 

 aperture very oblique, large, lunar-oval ; lip simple, 

 sharp, umbilical edge a little refli'ctcd. 



Gbiffith, Binney, Joum. Nat. Hist. Soc. Boston, vol. lii 

 p. 117. pi. 24. 



Hcdj. Pennsylvania, Ohio. 



.\ sombre olive-homy «pecie?, rather inflated in the Ih«1 

 whorl. 



