LAND-MOLLTJSCAN GENUS DTJRGELLA. 295 



Spire depressed. Suture impressed. Whorls 4, rather rapidly 

 increasing (PI. XX. fig 8). Aperture ovate, oblique. Peristome 

 very thin ; columellar margin not at all thickened. 

 Size — Major diam. 0'38, minor diam. 033, alt. axis - l7 inch. 



„ „ 9*5, „ „ 8-2, „ 4*4 millims. 



Animal. — The overhanging lobe to the mucous pore is largely 

 developed. The lateral pallial line is distinctly marked by a double 

 row of oblong segmental divisions or tubercles (PI. XX. fig. 5, s, s) ; 

 but the portion of the foot above it is smooth, with indistinct 

 radiating irregular lines leading to the dorsal side (s*). 



In PL XX. fig. 6, 1 give the mantle-lobes detached from the body 

 of the animal. They are as in D. levicula, only that the left dorsal 

 lobe is divided into two distinct parts at about the middle of its 

 length. 



Generative Organs (PI. XXI. fig. 2). — The albumen-gland is 

 pear-shaped and well developed, with an expansion near the 

 junction of the hermaphrodite duct. The oviduct is greatly 

 swollen and enlarged, but, as usual, not well preserved. The 

 spermatheca (sp) longer than in D. levicula, with the same swollen 

 posterior termination and narrow median neck. The penis shows 

 expanded portions in its course on both sides of the retractor 

 muscle. No amatorial organ found in two specimens examined. 

 Here we have a most interesting correspondence with what Sto- 

 liczka has recorded on the anatomy of Conulema (J. A. S. B. vol. xl. 

 1871, pp. 236-241, pi. xviii.), where he found it present in G. 

 attegia, Bens., from Burmah, not so in G. infula, Bens., the Bengal 

 or Indian form. This I take to be another proof of the close re- 

 lationship of -the genus Durgella and Gonulema in the two areas ; 

 for we find that D. assamica bears exactly the same relationship 

 to G. infula as D. levicula does in Burmah and Tenasserim to 

 G. attegia — a modification from some older, earlier, and wider- 

 distributed form having gone on in the two areas. But it would 

 not, as Stoliczka says, be expedient, on this single point of struc- 

 ture alone, to place attegia and infula in different genera. On 

 the contrary, it would be more in accordance with a strict classi- 

 fication to consider Durgella and Gonulema as one, in spite of the 

 very different and conchologically extreme form of their shells. 



The odontophore (PI. XXI. fig. 4) is as in D. levicula; the 

 central tooth not seen. The jaw (PL XXI. fig. 6) very straight 

 in front, thin, flatly convex above, rather narrow ; the striate lines 

 of muscular attachment form a broad arch over the central portion 

 of the front edge. 



