1894.] LAIJ^D-SHELLS FEOM THE SAMUI ISLA.VDS. 147 



eolumellari suhohsoleto, nodiformi, dentihus in. margine e,rterno 

 appro.vimatis subcequalib lis. 

 Diam. lU*5, alt. 7 imllim. 



By the flatter spire and the stronger distortion of the last whorl 

 to the right this form appears at first sight to be very different ; 

 and as there are some differences iu the dentition as well, I feel 

 almost inclined to separate it specifically. Having only one speci- 

 men of the variety and but two of the type, I leave this question 

 for further study. 



2. Stbbptaxis sriRiPiccs, sp. nov. (Plate XVI. figs. 1, 2.) 



T. umhilicata, depressa, subtilissime striatida, nUeus, pellucida, 

 Tiyalina. Anfractus 5|, planulati, superi spiram regularem 

 jjerplanam apice fere immerso efficientes ; penidtimus ad pen- 

 pJwriam acute carinatus ; ultinms ma.vime distortus, valde 

 e.vcentricus, basi peadiariter impressus, ad apertumm valde 

 compressus, subtus subacute cristatux, sat deflexus. Apertura 

 maxime obliqu:i, peranciu,sta, irregulariter cordiforniis; peristoma 

 sat expansum, albo-labiatum. Lamella pariefalis percdta, valida, 

 lonr/e infrans, sujierw bicraris, utrinque in callum parietalem. 

 desinens. 

 Diam. 9, alt. 4 millim. 



A fine new species of the group of S. exacutus, Gld., and S. han- 

 let/anus, StoL, both from Moulmein, distinguished by the entirely 

 plane spire with almost immersed centre, the bifid parietal lamella, 

 the compressed cordiform aperture, &c. 



3. Stbeptaxis boebeleni, sp. nov. (Plate XVI. figs. 3, 4.) 



T. aperte umbilicata, depressa, subtiliter arcuaihn costulata, tenuis, 

 pellucida, liyalina. Anfr.^ 6, convexiusculi, sat lente acerescentes, 

 superi spiram, subregularem depresso-conoideam efficientes ; pen- 

 ultimus viv, ultimus pauUum distortus, basi subinjlatus, glabra- 

 tus, pone aperturam coarctatus. Apertura diagonalis, truncato- 

 elliptica ; peristoma sat expansum rejlexiusculum, albo-labiatum, 

 margine externo jjrofunde sinuato, ad insertionem subito attenuato, 

 recedente. Lamella parietalis valida triangulariter elevata, 

 dentibus 3 lamelUformibus in margine externo et basali et nodulo 

 in columella oppodtis. 

 Diam. maj. 8-5, min. 7, alt. b-2o millim. 

 Forma major : diam. maj. 10, min. 8, alt. 5-5 millim. 

 Forma minor : „ 7'^ „ 6, „ 3" / o „ 



I find no recorded form of Streptaxis with which this interesting 

 species could be united. According to the rather meagre descrip- 

 tion, ;S'. elisa, Gld. (Proc. Bost. Soc. vi. 1856, p. 12 ; Pfr. Mon. Hel. 

 v. p. 448), of the Mergui Archipelago, must be somewhat similar, 

 but is larger, has one whorl more, the wkorls are angulate or 

 carinate, and there are two parietal lamellae. Both species are by 

 their depressed and almost regular form, with very httle distortion, 

 rather isolated among the Asiatic Streptaxes ; in the somewhat 



10* 



