OO LAND AND FRESHWATER 



apertura obliqiia, lunari, latiiiscula, 2>eristomafe tenuissimo, intiis iion 

 labiato, margine columellari superne brcviter rejlexo. 



" Diam. major 32, minor 28, axis 14 mill. 



" Habitat prope Bombay et Ahmedaugger, 



" I have had specimens of this shell from Dr. Jerdon, Major 

 H. Alexander, Mr. Fairbank, and others. Mr. Shurtleff assigns it 

 to H. lahiata. It has also been considered a variety of H. vitri- 

 noides. Besides its great thinness, the absence of any labiation 

 inside the peristome, and of the colours observable in the aperture 

 of B. lahiata, Pfr., -which I discovered, in 1838, in the Western 

 Himalaya, it is distinguished by its subangular periphery and 

 marginate suture from that and any other allied form." 



Shell. The surface of the shell under high power is quite smooth, 

 with not a trace of any longitudinal striation. 



Animal. Pale throughout, with a pale grey neck ; surface of the 

 body rather smooth. The sole of the foot is divided *. The peri- 

 podial groove as usual, but not very broadly fringed below ; the 

 grooves running from it upwards to the keel of the foot behind are 

 set at very regular intervals. There is a very short rudimentary 

 right shell-lobe (fig. 1, rsl), which in life cannot be extended very 

 far over the shell ; there is also a pointed small left shell-lobe, 

 given off from a narrow border on the margin of the peristome at 

 the left lou er side. The right dorsal lobe is ample, the left is in 

 two separate parts, with a wide interval between them; the anterior 

 portion does not extend far and has a long lobe, the posterior part 

 is narrow and rather short. The mucous pore just extends to the 

 margin of the foot ; the extremity is rather square. 



The odontophore has this arrangement of the teeth : — 



44 . 3 . 14 . 1 . 14 . 3 . 44 

 61 . 1 . ()1 



Central tooth tricuspid, cusps basal ; the median teeth tricuspid, 

 the outer cusp basal, the inner high ; laterals elongate, curved, 

 bicuspid, the outer much below the apical one. 



Oenerative organs (fig. 2). The penis is folded on itself below the 

 retractor muscle, and a large portion of this bend is coalesced 

 together forming a thickened cylindrical mass, pointed above and 

 there giving off the retractor muscle. Closer examination of this 

 portion {crp) shows that it is bent over near the muscle attach- 

 ment for about 5 mm. of the terminal end (fig. 3 a). This tube or 

 sheath is continued downwai ds to the generative aperture ; the free 

 portion is 5 mm. or more up to the junction of the vas deferens, and 

 hei-e is a long thick blunt-ended flagellum or kalk-sac, 8 mm. in 

 length. When in natural position the flagellum is folded and lies 

 close beside the main sheath, about the middle of its length (see 

 fig. 3). 



* Care is necessary in the examination of the foot ; in some eases bad preser- 

 vation in alcohol obliterates the lines of division, so that the middle and side 

 areas are not distinguishable. A series of specimens, as in this case, settled the 

 point. 



