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THE FEESHWATBR MOLLUSCA OF TIRHOOT, BENGAL. 



By 



Gordon Dalglibsh. 



Below I give a list of a few species of freshwater shells which were collected 

 for me in Tirhoot, Bengal. The list of course is extremely scanty, but I am 

 endeavouring to get friends in India to collect me more, and if their efforts are 

 successful I shall record them in the journal and send specimens to the Society's 

 museum. From an economical point of view freshwater shells play an important 

 part, quantities of lime being made from them, which is used for various pur- 

 poses in the Indigo districts of Bengal, the commonest shells used for this pur- 

 pose being Vivipara bengalensis , while other shells are used to collect the juice 

 of the poppy in for the manufacture of opium, Ampullaria globosa being chiefly 

 employed. The distribution of our Indian freshwater Mollusca is very imper- 

 fectly known and I was glad to see in a recent number of the journal an appeal 

 to members to collect shells for the Society's museum. I regret that while I 

 was in India I did not pay much attention to the Mollusca of the district I was 

 in, as I feel sure the result would have been satisfactory. 



GASTEROPODA. 



Fam. Viviparid.^;. 



Vivipara bengalensis (Lmk.). This is the shell par excellence of Tirhoot, being 

 exceedingly common in jheels and paddy fields. It is largely used in the 

 manufacture of lime. 



Vivipara clissimilis (Mull.). Common, but not so much so, as the last. It is 

 found in more or less abundance in jheels and lakes. 



Vivipara crassa (Hutton). Two specimens from Munjoul, 1902. 



Vivipara prcemorsa (Bens). One specimen from Munjoul, 1902. 



Fam. Ampollaeiid/e. 



Ampullaria globosa (Swain). The large and handsome "Apple Snail" is found 

 on the larger jheels and rivers, where the animal may often be seen floating on 

 the surface of the water. The shell is used to collect opium in. 



Fam. LimNjEID/e. 



Limncea acuminata (Lam.). Fairly common in ponds and rivers. 



Limncea rufescens (Gray). It is doubtful whether this should stand as a dis- 

 tinct species or merely a variety of L. acuminata. Mr. E. A. Smith, of the 

 British Museum, wrote to me regarding it as follows : — " Gray's Limncea rufescens 

 I regard as a variety of L. acuminata (Lam.) differing only in being rather 

 more slender with a longer spire, but aU intermediate forms are met with." 

 Two or three of this species or variety were sent to me along with L, acuminata 

 and it was only lately I detected the difference in the two forms. 



Limncea bulla ( ). Scarce. A few specimens only. 



