185S.] Notes on some Indian Freslnvater Shells. 317 



The Himalayan region has only been partly examined by me, and 

 I shall therefore confine myself to its eastern portion, availing 

 myself to some extent of the observations of my colleague Mr. ~W. 

 Blanford, who obtained, when at Darjiling, several shells which had 

 escaped my notice. 



The central region commencing in the plains below the lower 

 slopes of the hills, embraces the entire area outside the hills, 

 drained by the Ganges and Mahanadi to the east, the Nurbudda and 

 Taptee to the west, and the Indus and its tributaries to the north., 

 west, .a large and important area, but of a richness by no means 

 commensurate with its extent. 



Of the southern region, I know nothing personally, but the known 

 shells of that quarter sufficiently support its claim to rank as an 

 independent division. 



Khasia Hills. 



The shells which are here given have mostly been named and 

 described by Mr. Benson, save in one or two instances, though many 

 names are still merely manuscript ones, but for practical purposes 

 I think a mere description unaccompanied by a figure of the shell 

 is of little use in discriminating between nearly allied forms, though 

 required by custom to establish the currency of the name applied 

 to a new species. 



CYCLOSTOMIDJi!. 



JPterocyclos, Bensojt. 



No. 1. JP. Hispidus, Pearson. — Teria ghat at the foot of the hills 



on the road to Cherra. This handsome species is very abundant on 



rocks at the limestone quarries a little above Teria ghat, where a 



dwarf variety also occurs sparingly. Diameter over peristome, 1.20. 



Ditto in dwarf, 0.70. 



2. P. Alhersi, Pf. — Teria ghat. A dwarf variety. 



Cyclophorus, Montfort. 



3. C. Siamensis, Sow. — Teria ghat (the quarries). This very 

 handsome species occurs abundantly. The apex is generally imper- 

 feet, probably from falling among rocks ; as it is a heavy shell. 



4. G. Pearsoni, B. — -Lacat. Very common. Varies in size 

 1.90 1.20 



from to 



1.50 0.90 2 t 



