auriculid^e. 110 



2. Leuconia Micheli. 



Shell imperforate, ovate-conic, thin, faintly striated, dia- 

 phanous, slightly shining, whitish-yellow ; spire conic, rather 

 pointed ; suture linear ; whorls six and a half to seven, scarcely 

 convex, the last forming about four-sevenths of the total length, 

 rather attenuated at base ; aperture scarcely oblique, semiovate, 

 rounded in front, furnished with two plaits; parietal plait 

 middle-sized, somewhat transverse ; columella! plait callous, 

 slightly twisted; peristome rather simple, straight; right margin 

 slightly sinuate above, columellar margin adnate. Length 5|, 

 greatest breadth 3 mill. 



Auricula Micheli, Mittre in Revue Zool. 1841, p. 66. 

 Leuconia Micheli, H. and A. Adams in Proe. Zool. Soc. 1854, 

 p. 36. n. 4 ; Gen. rec. Moll. ii. p. 248. 



Pfr. Syn. Auric, n. 167 ; Mm. Auric, p. 156. 

 Hob. Coasts of Mediterranean Sea, near Toulon. 



3. Leuconia Bivon.s:. 



Shell imperforate, ovately fusiform, extremely thin, smooth, 

 pellucid, glassy ; spire conic, rather pointed ; suture simple, im- 

 pressed; whorls seven, moderately convex, the last scarcely 

 longer than the spire, much attenuated at base ; aperture nearly 

 perpendicular, narrow, semielliptical, furnished with two plaits ; 

 parietal plait middle-sized, compressed; columellar plait oblique, 

 twisted, not reaching the base of aperture ; peristome simple, 

 straight, with the columellar margin not dilated. Length 5, 

 greatest breadth k 2\ mill. 

 Ovatella bidentata, Bivona, Nuov. Gen. p. 22. t. 2. f. 10 : not 



Montagu. 

 Auricula myosotis, /3, Philippi, Sicil. i. p. 143. 

 Auricula Brvonse, Philippi, Sicil. ii. p. 118. 



Kmt. Auric, p. 20. t. 2. f. 14, 15. 

 Leuconia Bivona?, H. and A. Adams in Proc. Zool, Soc. 1854, 



p. 36. n. 5 ; Gen. rec. Moll. ii. p. 248. 



Pfr. Syn. Auric, n. 168 ; Mon. Auric, p. 156. 



Hub. Sicily. 



4. Leuconia occidentals. 



Shell oblong, extremely thin, smooth, diaphanous, pale liorn- 

 coloured or whitish ; spire regularly conoidal, rather pointed ; 

 whorls five to six, scarcely convex, the last forming about five- ' 

 sevenths of the total length, somewhat turgid above, slight!/ 

 attenuated at base; aperture nearly perpendicular, narroWl 

 semiovate ; parietal plait single, middle-sized below the middle: 



