BY E. M. JOHNSTON, F.L.8. 



101 



(lxiii.) Family Sttccineids. 

 Genus Succinba. (524-525.) 

 Shell oval, very fragile and transparent; spire short; the 

 whorls few, and very rapidly enlarging ; aperture 

 oval ; outer lip thin, not reflected, united below by a 

 very broad curve with the thin, smooth columella. 

 Dist. — World-wide ; sub-aquatic, living in damp places, 

 near the margin of streams. 



(lxiv.) Family Aueiculid^:. 

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

 conoidal, very rarely sub-elongated ; 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, with- 

 out teeth.) 



Genus Cassidula. (526-529.) 

 Shell sub-perforated, 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, sinuous ; inner lip dentately plicate ; 

 columella plication strong ; outer lip thickened within 

 by a strong callosity with toothed edge. Dist. — Ceylon, 

 East Indies, Philippines, Australasia, Polynesia. 



Genus Alexia. (527.) 

 "hell oblong-oval, thin, spire acuminate ; last whorl large, 

 rounded at base ; columella with an oblique plait ; 

 aperture contracted by teeth, and sometimes by a 

 callosity of the outer lip. Dist. — United States, West 

 Indies, Maderia, Europe. 



Genus Mabinula. (528.) 

 oval-oblong, imperforate, solid, smooth ; spire short, 

 sharp ; aperture oval ; inner lip rather thick, excavated 

 with three plications, the posterior largest ; outer lip 

 simple, sharp. Dist —Australia, Mediterranean, W. 

 Coast of America. 



Genus Ophtcaedeltts. (529.) 

 knell oval-oblong, umbilicated, smooth ; spire elevated-conic ; 

 aperture oval, elongated, angulated above ; inner lip 

 reflected, with two spiral plications, one of which 

 surrounds the umbilicus ; outer lip thin, simple. 

 Dist. — Australia, Polynesia. 



Shell 



