EXPLANATION OF PLATE IV. 

 All the figures are frora direct photographs of natural size. 



Vivifara crassispiralis, sp. nov. 

 Fig. I. — Type-specimen, from the Manipur Valley. 



Vivipara oxytropis (Benson). 



Fig. 2. — Male shell from the Loktak Lake, Manipur. 



,, 3. — Female shell from the same locality. 



,, 4. — Normal female shell of pond phase, from Imphal, 

 Manipur. 



,, 5. — Very large male shell of the same phase, from the 

 same locality. 



