96 LAND AND FRESHWATER 



surface of the shell ; below this, following the body-wall, a broad 

 elongate lobe covers the underside, and passes backward behind the 

 shell in a narrow fringe to unite with the left shell-lobe. This is 

 narrow throughout, just overlapping the peristome : a small tongue- 

 shaped process is given off on the left margin, similar to that of 

 typical MacroMawys. The dorsal lobes are very much developed, 

 the left dorsal one is in two parts. 



Genitalia. The amatorial organ present. The male organ is 

 simple, the kalk-sac very small, represejited by a bulbous swelling ; 

 above this there is a sharp bend in the sheath, the retractor muscle 

 rising from the end of it. 



Jaw with a slight concave edge, soft in structure, and merging 

 on its upperside into the muscular tissue. 



The odontophore has plain, straight-sided, rather bluntly pointed 

 teeth in the middle area ; the numerous laterals are evenly bicuspid. 

 The radula is broad, and has over 200 teeth on each side. 

 Shell with few whorls, thin, transparent ; body-whorl large. 

 As to its phylogeny. It is of much interest to compare the male 

 organ (vide Plate LXXXY. fig. 6) with that of Euplecta, for if the 

 very short tube between the bulbous kalk-sac and the base of 

 the muscular retractor muscle were greatly lengthened we should 

 have precisely the same loop as seen in Plate LXXXVI. fig. 4 h. 

 Yet still more like is the male organ to that of Nilqiria chenui 

 (Plate XCVI. figs. 6 & 7) and Ariophavta dalyi (Plate XCVIII. 

 fig. 4). It shows that, as regards this part of the internal aiiatomy, 

 the relationship of this genus is with these genera of the Ario- 

 phantinae. 



Genus Euplecta, Semper. (Plates LXXXVI. & LXXXVII.) 



A list of species included in the genus was published by me in 

 18y7, in the ' Proceedings of the Malacological Society,' vol. ii. 

 pt. 4, p. 173, and I extract a portion of Avhat I then wrote : — 



" In 1880 Mr. W. T. Blanford * referred to Semper's work, and 

 pointed out the confusion that inevitably arises from describing two 

 species as the type of a genus and adopted the one that btood first, 

 viz. E. subopaca. There are several marked differences between 

 this and Semper's second siDceies, E. layardi. The jaw of the first 

 has a central projection, while in E. layardi there is none ; in the 

 radula the elongate form of the central teeth of the first species is 

 very different to the shorter blunter form of the second ; the 

 number of teeth in each row is as 100 to 140-160 respectively, 

 this being the most striking difference. . . . The genitalia of these 

 two species are, however, very much alike ; in both there is a short 

 sessile spermatheca, perhaps a more important generic character 

 and one less liable to change than the odontophore. . . . Mr. Blan- 

 ford was the first to examine this genus from an anatomical jwint 

 of view, when treating of the position of other Indian species 

 unknown at the time of Semper." 



* Journ. Asiat. Soc. Bengal, vol. xlix. pt. 2 (1880), p. 191. 



