1865.1 Contributions to Indian Malacology. 75 



Tsanda Khyoung, it was abundant, but it was not met with again 

 until 3 or 4 specimens of the larger variety were found nearly 50 

 miles further south. 



The locality given by Mr. Benson for Helix leiophis is Kwadouk 

 near Thayet Myo. The shell also abounds at Akoutoung, on the 

 Irawady, below Prome. 



13. H. PERARCTA, U. Sp. 



Shell sinistral, widely umbilicated, discoid, rather thin, white, 



transversely sinuously striated, with faintly marked decussating spiral 



lines above and below. Apex minutely granulate, slightly raised 



above the flat spire, suture rather deeply impressed. Whorls 6, 



convex above and at the periphery, the last a little compressed behind 



the mouth, descending suddenly to the aperture, which is oblique and 



roundly lunate ; peristome white, expanded all round ; margins joined 



by a somewhat curved ridge, from the centre of which a lamella runs 



up the whorl towards the parietal plication, which, however, it does 



not join. The parietal vertical lamina is single, simple, rather short, 



slightly curved, with a rudimentary transverse plait at the top. Two 



free horizontal lamella? occur beneath that running to the aperture, the 



lowest being the longest and thinnest, and running back beneath the 



base of the vertical lamina. Palatal teeth 6, all horizontal except the 



4th and 5th, which are slightly oblique. Umbilicus open, deep, 



exposing all the whorls. 



Millem. inch. 



Major diameter, 11 0.44 



Minorditto, 9 0.36 



Height, 4 0.16 



Habitat — Mya Leit Doung, near Ava. 



Distinguished from its allies, H. refuga, H. leiophis, and H. Kareno- 

 rum, by its deeper suture and rounded whorls, and internally by the 

 shorter parietal lamina, and by the 5th palatal plait being less oblique 

 than in leiophis, and not backed by a second plait as in refuga. This 

 species is the smallest known amongst those belonging to the Burmese 

 types of Plectopylis. 



14. H. Feddeni, n. sp. 



Shell sinistrorse, very widely umbilicated, discoid, flat above, thin, ' 

 dull white, marked by rather irregular oblique sculpture both above 



