4^6 Records of the Indian Muscuui. [Vol. XXII, 



var. sumatrensis (Bret). 



1S7.),. Melania sumatrensis, Brot. op. cit., pp. y;, 88. 



1885. Melania {Melaiibide^) variabilis, Nevill, Hand-List Moll. Ind. 



Mils. II, pp. 251, 252. 

 1897. Melania. (Brotia) sumatrensis, \. Martens, op. cit., pp. 34-36. 

 1900. ? Melania {Brotia) episcopalis. v. M;irtens. Nadir. Dent. J\fala- 



kozool. Ges., X.XXII, p. 10. 



In spite of what von Martens has said regarding the validity 

 of this species, I do not think that it is possible to separate it 

 from A. variabile. Nevill interpreted its relationships correcth', 

 but was mistaken in considering Brot's species as a mere synonym 

 of Benson's. Probably' he was led to this conclusion by the very 

 different forms figured by Brot as representing his species. It 

 might have been a better course to have dropped Brot's name 

 sumatrensis and adopted the earlier varicosa, Troschel, for the 

 Sumatran form, but as Troschel's original specimens caiiie from 

 the River Ganges, India, this form was probably the forma typica 

 or one of the various Indian varieties of the true variabile. 

 The Sumatran shell recorded by v. Martens as M. episcopaUs, in 

 the paper cited above, appears from the short note appended to 

 have probably been this form. I have no doubt, however, regard- 

 ing the one he described as M. siimitrensis in his first paper, 

 for I have seen one of the specimens named by him. 



The form I consider as Brot's sumatrensis is widely distri- 

 buted in Sumatra. It is well represented by Brot's figure la (pi. 

 xiii). The shell of this form is fairlj- massive, pyramidal, with 6-9 

 persistent whorls increasing more or less evenly in size, the suture 

 is oblique and moderately impressed and the whorls have well 

 developed oblique varices or rather ribs. The ribs, though 

 feeble on the upper whorls, are quite distinct on all of them ; the 

 body-whorl has at least ten distinct ribs. The aperture is ovate, 

 somewhat pointed posteriorly and produced but rounded anteriorly. 

 The shells are uniformly coloured, being chestnut-brown or even 

 black. The aperture has a black margin though the mouth 

 further inwards is bluish or even whitish. 



The following are the measurements (in millimetres) of six 

 specimens from different localities : — 



This is a true stream form, and in Mr. den Doop's collection 

 is represented by a large series of specimens of all ages from the 

 following streams: — Soengei Kalau (near Bohorok), streamlet at 

 Timbang I^angkat, Bah Endah, Soengei Lepan (L,angkat), Soengei 

 Minahol and Soengei Bohorok (lyangkat). 



