28 Records of the Indian Museum. _[Vor. XVIII, 
evidently rare in most parts of Seistan. Single fairly fresh but 
empty shells were collected at the edge of pools near Nasratabad 
and Jellalabad and at that of the Hamun near Lab-i-Baring, while 
a considerable number of bleached specimens were also observed 
in the soil of occasionally flooded country near Chilling towards 
the south of Seistan. It is not improbable, therefore, that V. 
hilmendensis is common on the banks of the lower Helmand and is 
essentially a fluviatile species. 
Tvpe-series. M 5087/1, Zoological Survey of India (Ind. 
Mus.). 
Family MELANIIDAE. 
Melanoides, Olivier. 
1807. Melanoides, Olivier, Voy. l’Emp. Ottoman II, p. 40. 
1854. Plotia, N. and A. Adams, Gen. Rec. Moll., p. 295. 
1874. Plotia+Striatella (? in part), Brot, Melanztaceen in Martini and 
Chemnitz, Conch. Cab. (ed. Kuster), p. 7. 
1897. Melanoides+ Plotia, v. Martens, ‘‘ Suss. und Brackw. Moll.’’, pp. 
50, 62 in Weber’s Zool. Ergebn. Niederl.-Ost-Indien 1V. 
1898. Neomelanien, P. and F. Sarasin, Sussw. Moll. Celebes, p. 38. 
1915. Striatellat+Plotia, Preston, Faun. Brit. Ind., Freshw. Moll., pp. 
15, 35: 
In discussing the species of Melania (s.l.) that occur in Balu- 
chistan and Seistan we have had to overcome two difficulties, 
firstly to settle the somewhat complicated specific synonomy, and 
secondly, to decide what characters should be regarded as of 
generic importance. So far as the second of these questions is 
concerned we have followed in the main the classification adopted 
by the Sarasins in the work cited above. We have, however, 
regarded the groups that they include under the name Melama as 
of generic value, believing that by so doing we are following sound 
lines in estimating such structures as the operculum and radula 
as of equal value in this family to the sculpture of the shell and the 
precise form of its mouth. The groups or subgenera Plotia, and 
Striatclla (== Melanoides) as defined by Brot in his monograph and 
accepted by Preston in the Fauna of India, fade imperceptibly one 
into the other, and Brot’s diagnosis of Ploiia is, as we have pointed 
out elsewhere,'! by no means applicable to all shells even of the 
type-species. 
The question of specific identity and nomenclature in the 
Indian and Persian species of the genus is complicated by imper- 
fect descriptions, particularly on the part of Troschel and Philippi. 
In considering the question due but not excessive attention 
must be given to the locality of specimens and it must be remem- 
bered that the names Melania pyramis and M. elegans are due to 
Hutton, and not to Benson, who merely distinguished certain forms 
by letters, and that, further, Hutton was dealing very largely 
1 Rec. Ind. Mus. XIV, p. 147 (1919). 
