pulmonata. 73 



20. Helicarion aperta. 



Shell much depressed, slightly convex above, wide open at 

 the base, smooth, subopake, greenish-white ; spire minute, 

 lateral ; suture smooth ; whorls two and a half, slightly convex, 

 very narrow at the base, wide open, the last very large, smoothly 

 vaulted ; aperture horizontal, ear-shaped, open to the apex ; pe- 

 ristome quite simple. Lat. maj. 11, min. 8, alt. 3 mill. 



Vitrina aperta. Beck, MSS. 



Pfr. in Proc. Zool. Soc. 1848 ; Mon. Helic. ii. 502. 



Hab. Luzon, Philippines. 



9*. Platycoster, only known from the following short ac- 

 count, is probably one of the Vitrina of Pfeitfer. " It approaches 

 the genera Helix and Vitrina, but a difference in the shell in- 

 duces me to separate it." — Hasselt. 



Platycoster, Hasselt, Bull. Sci. Nat. iii. 82, 1824 ; Proc. Zool. 

 S'oc. 1847, 169. 



Philippi, Handb. Conch. 481. 

 Ilelicopsis, sp.. Beck, Index, 1837. 



1. Platycoster corneus. 



Platycoster comeus, var., Hasselt, Bull. Sci. Nat. iii. 82, 1824. 



Hab. Java. 



10. NANINA. 



Shell perforated, depressed, polished, smooth above and below. 

 Mouth lunate or lunate elliptical ; peristome the thickness of the 

 shell, straight ; columellar lip short, reflexed, very often covering 

 the perforation. Mantle edge thick, prominent, with a more or 

 less large lobe on each side ; the left expanded on the lower 

 part of the whorls. Foot narrow, truncated behind, with a 

 short conical process above the truncation ; gland linear, erect. 



Vitrina, sp., Quoy Sf Gaim. 



Blainv. Man. Malac. 654. 

 Nanina (citrina), Gray, Proc. Zool. Soc. 1834, ii. 58 ; 1847- 

 Macrochlamys (vitrinoides), Benson, MSS. Journ. Asiat. Soc. 



Beng. 1832, j. 13, not described. 

 Tanvchlamys (vitrmoides),Benso«,i¥SS./oMr«. Asiat. Soc.Beny. 



1834. 

 Stenopus, part., Gray, Proc. Zool. Soc. 1847, 169. 

 Ilelicopsis, Beck, Ind. 

 Microcystis, Beck, Ind. 

 Nauinia, Sow. Conch. Man. 198. 1842, misprint. 



B 



