AURICULID^. 93 



the sea ; mostly tropical in distribution, at least as to the larger 

 species. 



The inner walls of the whorls are nsuall}'^ absorbed, so as to 

 form a single cavitj^ for most of the interior (i, 14). 



Auricula, Lam., IT 99. 



Etym. — Auricula^ a little ear. 



;Siyn.— Ellobium, Bolten? 1798. Marsyas, Oken, 1815. Ge- 

 ovula. Swains., 1840. Auriculus, Montf., 1810. 



Distr. — 44 sp. East Indies, New Caledonia, South America, 

 Philippines, Australia. A. Midae^ Linn, (cii, 70). 



Shell oblong-oval, covered by a thin epidermis ; spire short, 

 conoidal, ver}^ rarely subelongated ; last whorl large ; rounded 

 at the base ; aperture longitudinal, narrow, ear-shaped ; inner 

 wall of the aperture with two or three plications ; peristome 

 thickened internally, without teeth. 



A. Judae, Linn., has truncated tentacles. The species are 

 mostly fonnd in brackish-water swamps, in tropical islands, and 

 several of them are known to be blind. 



siONA, H. and A. Adams, 1858. (Sarnia, H, and A. Adams, 

 1855.) Shell oval-cylindrical; spire obtuse; whorls transversely 

 striate; aperture linear; inner lip plicate; outer lip thickened 

 within, sinuous behind, A. avena, Petit. 



PYTHioPsrs, Sandberger, 1870. Shell oval-conic, with a line of 

 varices, sometimes on one side, sometimes on both sides ; colu- 

 mellar wall with two plications, the posterior small, the anterior 

 subhorizontal ; base of the columella plicate and twisted ; lip 

 thickened within but not dentate. A.ouata,'La.m. Eocene. This 

 group connects Auricula with Scarabus. 



AURicuLASTRA, Martens. Aperture with thickened lip ; shell 

 small, with elevated spire. A. subula, Quoy. 



Cassidula, Fer., 1819. 



Sj/'i. — Sidula, Gray, 1840. Rhodostoma, Swn., 1840. 



Distr. — 27 sp. Ceylon, East Indies, Philippines, Australasia, 

 Polynesia. Fossil ; G. umbilicata, Desh. Miocene of Touraine. 

 C. angidifera, Petit (cii, 71). 



Shell subperforated, cassidiform, solid ; spire short, conoidal ; 

 last whorl very large, attenuated to the base, where it is usually 

 carinated or angulated around the axis ; aperture narrow, sin- 

 uous ; inner lip dentately plicate ; columellar plication strong ; 

 outer lip thickened within b}^ a strong callosity with toothed 

 edge. 



Foot bifid behind ; tentacles slim and pointed, with eyes 

 slightl}^ raised at their internal base. 



Usually inhabits mangrove-swamps, and among loose stones 

 near the sea-shore ; some species are amphibious, and at high 



