290 AMERICAN JOURNAL 



2. Helix Venosus, Pease.— t. 20, fig. 2. 



Description. — T. orbicularis, glabra, imperforata, tenuis, 

 spira subconica, obtusa; anfr. 5, convexiusculi, gradati, ulti- 

 mus ad peripheriam cariuatus, basi convexus ; apertura ovato- 

 lunaris. Pallide cinereo-lutescens, lineis tenuis, nigricantibus, 

 radiatim et concentrice ornata. 



Dimensions. — Diam. 8, alt. 5 mill. 



Shell orbicular, imperforate, thin, shining; spire somewhat 

 conically elevated, obtuse; whorls 5, planely convex, the last 

 carinate at periphery, base convex; aperture ovately lunate. 

 Color greyish-yellow, base darker, ornamented with line con- 

 centric blackish lines, and with faint radiating stripes and 

 lines of the same color. 



3. Helix frivola, Pease.— t. 20, fig. 3. 



Description. — T. parva, subgloboso-conica, tenuis, lsBvis, 

 o-labra, imperforata; anfr. 4, obsolete carinata, sutura impressa, 

 vix marginata; apertura obliqua, lunato-ovalis. Pallide 

 straminea. 



Dimensions. — Diam. 5f , alt. 3| mill. 



Shell small, somewhat globosely conic, thin, smooth, shining, 

 imperforate ; whorls 4, obsoletely roundly carinate at periph- 

 ery, suture impressed, finely marginate ; aperture oblique, lu- 

 nately oval. Color pale straw. 



4. Helix distans, Pease. 



Description.. — T. tenuis, planorboidea, depressa, pallide cas- 

 tanea, oblique costato-striata, supra planulata, spira parum 

 elevata ; anfr. 4-5, convexis, ultimo magno, rotundo, basi sub- 

 angulato, sutura impressa ; apertura magna, vix obliqua, sub- 

 circularis, ad parietale castellis intro volvente instructa ; urn- 

 bilico £ diametri subasquante. 



Dimensions. — Diam. 7, alt. 2h mill. 



Shell light, thin, planorboid, depressed, light chestnut, oblique- 

 ly ribbed- striate, plane above, or spire very slightly elevated ; 

 whorls 4—5, convex, the last large, rounded, on its base slightly 

 obtusely angulated, suture impressed ; aperture large, nearly 

 circular, and somewhat oblique, a number of rib-striae, re- 

 volving within on its base ; umbilicus open, wide, comprising 

 about one-third of the diameter of the shell. 



Habitat. — Sandwich Islands. 



Belongs to the Hystrix group of species, and is the most 

 distant from the type, of any heretofore described. 



