LAND-MOLLTJSCAN GENUS DURGELLA. 293 



4. The odontophore is broader than long, with a central minute, 

 tricuspid tooth ; the lateral teeth all similar, minutely 6-cuspid 

 or pectiniform, on a curved edge, very closely set together and 

 exceedingly numerous. 170 — 1 — 170+ . 



5. In generative organs, an amatorial organ present in the 

 Burmese form is absent in the Indian. 



6. Shell thin or membranaceous, globose or depressedly conoid ; 

 polished, very closely perforate, the columellas margin having no 

 solidity. 



The abnormality of this genus, as compared with shells of 

 similar form, lies principally in the very remarkable odontopbore, 

 which is quite unlike any other Indian species of the Zonitidse 

 that I have examined ; with this, of course, we find the jaw also 

 much modified. There is considerable similarity with the teeth 

 of Conulema attegia and O. infula (figured by Stoliczka in the 

 J. A. S. B. 1871, pi. xviii. figs. 4 & 9) in the multicuspid or pec- 

 tiniform laterals and the greater number (153 on each side in 

 G. infula) ■ but the centre tooth is large and the shell-lobes of the 

 mantle are not developed ; still here we have relationship. 



Durgella levicula, Benson. (Plates XX. & XXI.) 



Locality. Meetan, under the Mule-it range, Tenasserim ; very 

 abundant (0. Limborg). 



Shell very narrowly perforate, ovately globose. Sculpture 

 smooth on last whorl, with regular shallow ribbing under a strong 

 lens ; the apical whorls are regularly and finely striate, crossed 

 by oblique fine ribbing, and almost decussate. Colour when living 

 pale greenish ochre, whitish towards the apex ; with animal re- 

 moved, very pale ochraceous. Spire low, convex. Suture rather 

 shallow. Whorls 3| to 4, adpressed, well rounded (Plate XX. 

 fig. 7). Aperture broadly ovate, oblique. Peristome thin ; colu- 

 mellar margin rounded, slightly reflected, not at all solid. 



Lai'ge specimen :— 

 Size — major diam. 0'35, minor diam. 0*30, alt. axis 0'18 inch, 

 s, , 5 9 - 0, „ „ 7-2, „ „ 4-5 millims. 



Diam. aperture 5*7, alt. aperture 5*0 millims. The ordinary 

 size, however^ is 7"0 millims., of the major diameter. 



Living Animal. — Pale ochre, with a dusky line on the upper 

 part of the extremity of the foot, also on the neck ; tentacles mode- 

 rately long ; foot with mucous gland (PI. XX. fig. 3 a), lobe over it 

 moderate, A broad tongue-like expansion (figs. 3, 4, & 6, r.s.l.) on 

 the right side of the aperture, another on the left margin of the 



23* 



