LEIOSTRACA, 



Plate I. 



Geinis LEIOSTRACA, 11. and A. Adams. 



Testa elongala, iiiidtispiraUs, poUla, varicdjus nidlis, apice 

 acuta, recto ; aperturd supenie acuminata, infra ro- 

 tundatd, labio interno reflcvo, plerutnqiie snbcompla- 

 nato, axi imperforato, labro suhincrassato ; operculo 

 cornea, ovata, snb.tpirale. 



Shell elongate, multispiral, polished, without varices, apex 

 sharp, straight ; aperture acuminate above, rounded 

 below, inner lip reflected, generally rather flat, axis 

 iniperl'orate, outer lip slightly thickened ; operculum 

 horny, ovate, subspiral. 



The more tyjiieal species o( Leiostraca are distinguished 

 by a slight flatness in front of the body-whorl, which, 

 however, is not very easy to detect in the majority. The 

 absence of varices is a more constant though negative 

 character, and this, with the straight apex and more elon- 

 gate form, will render the genus suflRciently distinct from 

 Enlima, to satisfy those who are interested in the more 

 recondite among generic divisions. 



Twenty-two species are enumerated in our Plates, of 

 which about half were given in Mr. Arthur Adams's mo- 

 nograph in Sowerby's 'Thesaurus;' many of the others 

 have been described by that gentleman subsequently, and 

 three are here described for the first time. 



Jamaica, Central America, Australia, and the Philip- 

 pines, have furnished species of Lciostraca, and six of the 

 new species ai'e among the numerous .Japanese discoveries 

 of Mr. A. Adams. 



Species 1. (Fig. a, b, Mus. Cuming.) 



LEiosTR.iCA VARiANs. Lei. tx'std elongatd, angiisld, 

 tenni, pallide fidvn , lale fiisco fasciatn, sea oarie/alva 

 et albo taniatd ; aperturd oblo)i(jd, superne an (just a ; 

 anfractibus oblongis, rectiuscuUs. 



The varying Leiostraca. Shell elongate, narrow, 

 thin, pale-fawn, with broad brown band, or variously 

 ribanded with brown and white; aperture oblong, 

 narrow above ; whorls oblong, rather straight. 



SowKRBY, Pro. Zool. Soc. 1834; Thes. Conch, pi. 170. 

 f. 33, 24. 



Hab. Xipixapi, Central America. 



Species 2. (Mus. Cuming.) 



Leiostraca subulata. Lei. testa angustd, eJongatd, 



tenia, pallide fidvd, fusca rubesceuli bifasciatd : an- 

 fractibus elongatis, paulh ventrlcosis, ultima subcvali ; 



aperttxrd elangatd. 

 The subulate Leiostraca. Shell nan-ow, elongate, 



thin, pale-fulvous, with two bands of reddish-brown ; 



whorls long, a little ventricose, the last rather oval ; 



aperture elongate. 

 Montagu. 



Helix flavo-eincta, Megerle. 



Melania Bonovard, Porbes. 



Ealima lineuta, Sowerby. 

 llab. British Islands. 



The whorls are proportionately longer and a little more 

 swelled in this species than in the preceding. 



Species 3. 



Leiostraca recta. Z,ei. lestd semipellucidd, alba, palli- 

 dissime rosea tinctd, pi/ramiduli ; anfractibus paucis, 

 reclis, ultimo orali, cenlricoso ; aperturd lata, pijri- 

 formi. 



The straight Leiostraca. Shell semipellucid, white, 

 tinged with very pale-rose, pyramidal; whorls few, 

 straight, the last oval, ventricose; aperture wide, 

 pyriform. 



C. B. Adams, Shells of Panama. 



llab. Panama. 



A thin, white shell, with a very slight tinge of rose. 



Species 4. (Mus. Cuming.) 



Leiostraca unilineata. Lei. testa curtd, subovali, 

 teuui, alba, lined spirali pallida cinctd ; anfractibus 

 pnucis, subinflalis ; aperturd pyriformi, elonijatd. 



The single-line Leiostraca. Shell short, rather oval, 

 thin, white, girt with a spiral line; whorls few, 

 slightly inflated ; aperture pyi'iform, elongated. 



Adams and Reeve, Zool. Voy. Samarang, p. 52. pi. 11. f.y.'i. 



Hab. Sooloo Sea. 



Shorter and more oval than any of the preceding, the 



last whorl occupying more than half of the entire length 



of the shell. 



May, 1866. 



