56 LAND AND FRESHWATER 



mucous pore (fig. 4) not extending to the foot-sole, the extremit yof 

 the foot above slightly overhanging it. 



Anatomy. On removing the shell the visceral mass (fig. 3) pre- 

 sents a single coil, the apical portion being distinct and blunt. 



Generative organs (fig. 7). The penis (figs. 7 6, 7 c) is a thick, 

 muscular walled tube ; there is a lower sac-like portion, suddenly 

 constricted and then dilating into a bulbous head. The very short 

 but strong retractor muscle (r.m.) is attached here, and from the 

 side of the bulbous head the vas deferens passes off" as a thick tube, 

 narrowing gradually as it approaches the common duct. The 

 spermatheca (sp.) is a small ovoid sessile body. The hermaphrodite 

 gland (fig. 7 a) is almost circular. The amatorial organ is a large, 

 thick, muscular walled tube, making a single coil about the middle 

 half, which would increase its elasticity and act like a spiral spring ; 

 just below this {sp.am.) is the calcareous dart (fig. Id); its basal 

 portion is funnel-shaped, and the dart itself long and pointed. 



The jaw (fig. 5) is straight and narrow, slightly concave on the 

 cutting-edge, with a straight central portion. 



The lingual ribbon (fig. 6) is broad and square, having a great 

 number of equal-sized and similarly-shaped teeth in the row. It 

 was incomplete in D. smithi, but showed +175 . 1 . 175 + . 



The central tooth is elongate, with three points, close upon the 

 same IoygI, JJeur-de-lis in form, contracting below this and widening 

 again at the base. The lateral teeth are all uniform, curved, very 

 elongate, with two closely-set points, the outermost being rounded, 

 the innermost sharp and pointed. 



Damayantia is in every respect a most interesting genus, diff'ering 

 in many important particulars from Girasia and its allies of the 

 Indian region. I give these differences verbatim from the paper 

 in the Proc. Zool. Soc. :— 



" 1. The spiral form of the visceral mass is very noticeable, and 

 we probably have here indicated a relationship with forms having a 

 more perfect spiral shell. In Girasia, when the shell is removed, 

 this is not apparent. The visceral sac is a globose mass. 



" 2. The form of the mantle-lobes indicates a relationship to some 

 form in which the left shell-lobe has become largely developed 

 along the whole mantle-edge together with the right, as displayed 

 in Girasia and Macrocldamys, but in which last-named the develop- 

 ment of the shell-lobes has been more equal and commenced at two 

 distinct points. 



" 3. The position and form of the caudal mucous gland. 

 "4. The straight jaw. 



" 5. The broad lingual ribbon and the great number of teeth of 

 a very different kind." 



These last two characters we find in DurgeJla ; they show a certain 

 approach to the subfamilj' Durgellina3. 



In Issel's original description of external characters only, and his 

 figures 4 and 6 of the type of the genus, D. dilecta, it is shown to 

 have exactly the same peculiar concentric markings on the mantle as 

 in D. smithi. Issel says, however, there is no shell, and this both 



