COLLINGE: NON-OPERCULATE LAND AND FRESHWATER MOLLUSCS. 89 



The penis is a large and muscular body enclosed within a muscular 

 sheath. There is a prominent retractor muscle inserted in its distal end. 

 The external orifice is common to the penis and the right Simroth gland. 

 I was unable to find any trace of a gland on the le:t side. Internally 

 the sheath of the penis has plicated walls, while arising from the distal 

 end of the cavity is a large muscular organ the penis papilla. This is 

 broad at its base, narrowing towards its free end which terminates as a 

 comparatively sharp point. Its external wall appeared longitudinally 

 indented or fluted, but this appearance is probably due to the pressure 

 of the plications of the sheath. On the left side, at the base of the 

 penis there is a small aperture which communicates with a folded duct 

 (PI. vi, fig. 61), this I succeeded in tracing as far as the inner side of 

 external male generative orifice. As previously pointed out, only a 

 single Simroth gland was found, the one on the right side ; I am quite 

 certain as to the absence of any such body on the left side. The 

 structure of the folded distal portion of that on the right side is shown 

 in transverse section in figure 62 (PI. vi.). On com[)aring this transverse 

 section with some recently made of the dart-gland of a Cingalese 

 mollusc (8), I have been struck by the extraordinary resemblance 

 they bear to one another, which has led me to inquire whether it is 

 not possible that the Simroth gland is a vestigial dart-gland ? 



The Pedal Gland (PI. vi, fig. 65). — This is a small tongue-shaped 

 body measuring 22 millim in length. Serial transverse sections were 

 made of the whole of the gland, and while agreeing in general with 

 Simroth's description, there were some points very different, but better 

 material is necessary before these can be discussed. 



Atopos hapmeri, n. sp. 



PI- V, fig. 43-45- 



Colour of the notum, light blue with darker blue blotches and 

 spots, a dark blue stripe extends along the mid-dorsal line, granulated ; 

 head yellow ; tentacles dark blue ; underside (perinotum ?) yellow ; foot- 

 sole yellowish-white with a faint median groove and transverse wrinkling; 

 keel only very feebly developed. Length of notum (in alcohol) 65-5, 

 breadth 12, height i4'5 millim. Breadth of foot-sole 7 millim. Female 

 generative orifice 13 millim. from the male generative orifice. 



Hah. — Kampong, near the borders of Kelantan and Ligeh. 



A young example of this species measuring 3 7 '5 millim. in length, 

 exhibits a much more prominent keel than the larger specimen. Judging 

 from the external features this species is probably allied to A. struhelli, 

 Simr. I have much pleasure in associating with this species the name 

 of Dr. S. F. Harmer, 



