HELIX.— Plate CXX. 



pressly globose, striated, lucid, white or ash-coloured, 

 sometimes oiie-bandcd ; whorls four to five, rather 

 convex, the last inflated at the base ; aperture luuar- 

 subcircular ; lip sharp, thickened within, coluincUar 

 margin reflected and dilated next the aperture. 



MomcAND, Mem. Soc. Nat. Hist. Geneva, vol. vi. p. 537. 

 pi. 1. f. 1. 



Hab. Texas. 



This species, wliich lias the appearance of a glassy bub- 

 ble, is very distinct from any of the North ^Uucrican 

 forms ; so much so, as almost to cast a doubt upon its 

 locality. 



Species 709. (Mus. Cuming.) 



Helix Hopetonexsis. Hel. testa umbilicata, subde- 

 pre8so-orbiculnri, undique creberrime coslato-striatd, 

 olivaceo-corned ; anfractibus quinque, rotundatis ; aper- 

 turd lunato-circulari ; peristoiiiate effuso, mbrejlexo, 

 intux labiaio, marginibus conniventUius, dente breci 

 albo ill pariele aperturali, margine columellari dentt 

 parvo, basali dente latiore, inunitk. 



The Hopeton Helix. Shell umbilicated, somewhat 

 depressly orbicular, very closely rib-like striated 

 throughout, olive-horny; whorls five, rounded; aper- 

 ture lunar-circular; lip ellused, a little rellected, tliick- 

 encd within, margins approximating, with a short 

 white tooth on the wall of the aperture, columcllai- 

 margin furnished with a small tooth, basal with a 

 broader one. 



Shuttlewortu, MS. 



Hab. Texas. 



A neatly closely ribbed rounded species, of a glossy 

 olive aspect, having three small tectli in the aperture, one 

 on the body-whori, and two on the inner edge of the liji 

 opposite. 



Hab. Cayenne; Petit. 



A shell of simple FlanorbUAAx growth, without any 

 indication of teeth in the aperture. 



Species 710. (Mus. Cuming.) 



Helix Cayennensis. Hel. testa umbilicata, discoidea, 

 striatulS, nitidd, corneo-lutescente ; spird subplanu- 

 lald; anfractibus quinque, vix convexiusculis, ultimo 

 vix dilalato, nou deacendente ; umfnlico magna, pervio , 

 fiperlurd lunato-circulari ; perislonuite simplici, acuta. 



liiE Cayenne Helix. Shell umbilicated, discoid, finely 

 striated, shining, horny-yellow ; spire rather flat- 

 tened ; wliorls five, but little convex, the last scarcely 

 dilated, not descending; umbilicus large, open; 

 aperture lunar-circular ; lip simple, acute. 



I'KEIFFER, Symbolffi, vol. ii. p. 21. 



Species 711. (Mus. Cuming.) 



Helix vultuosa. Hel. lettd umbilicata, depresto-orbi- 

 culari, undique creberrime costelUito-iitritda, o/iraceo- 

 carned ; spird convexd ; anfractibus sex, subangustis, 

 convexis, ultimo subobscure carinato ; umbilico jparvo, 

 profunda ; aperturd subquadrato-lunari, dent* pro- 

 minenle linguiformi in pariele aperturali ; perinlomale 

 incrassato, subrejlexo, margine columellari dente ob- 

 longo, dextro dente triangulari introterto, munitis. 



The ckim-looking Helix. Shell umbilicated, dt- 

 pressly orbicular, very closely rib-like striated 

 throughout, olive-homy ; spire convex ; whorls six, 

 rather narrow, convex, the last somewhat obscurely 

 keeled ; umbilicus small, deep ; apertimj somewhat 

 squarely hmar, with a prominent tongue-shaped tooth 

 on the wall of the aperture ; lip thickened, a little 

 reflected, columellar margin furnished with an ob- 

 long tooth, right margin with a triangular tootli 

 turned inwards. 



(iouLD, Pro. Nat. Hist. Soc. Boston, 18-48, p. 38. 



Jfab. Texas. 



This is very closely allied to H. Hopetonensis, but is 

 more closely convoluted, having a whorl more, and thert- 

 is a difi'ercncc in the form of the teeth. 



Species 712. (Mus. Cuming.) 



Helix Hindsi. Hel. testa angusti umbilicata, depressd, 

 subtiliter striata, corneo-lulescetite, diapluind, nilidd ; 

 spird parum elevatd ; anfractibus quinque, planitiscu- 

 lis, ultimo basi convexiore, ant ice dejlexo, subtus cvh- 

 strieto ; aperturd perobliqua, lunari ; peristomate bre- 

 viler reflexo, marginibus conniventibus, callo triangu- 

 lari dentiformi junctis, dextro lamella subrerticali, 

 basali dentibus aattis, munUis. 



Hinds's Helix. Shell narrowly umbilic^Ued, depressed, 

 finely striated, horny-yellow, diaphanous, shining; 

 spire but little raised ; whorls five, rather flat, the 

 last more convex at the base, deflected in front, i-on- 

 strieted l)eneath ; apcrtiu-e very oblique, lunar; lip 

 sliortly reflected, margins ai)proximating, joined l)y 

 a triangular tooth-shaped callosity, right margin fur- 

 Tiished with a nearly vertical lamella, basal with two 

 shar]) teeth. 



