INTER AND INTRA-SPECIFIC VARIATION OF THE SHELL OF TWO SPECIES OF THE TROPICAL FRESHWATER SNAIL BELLAMYA (MOLLUSCA: PROSOBRANCHIA)

Shell variation in two species of the tropical freshwater snailBellamya from two different habitats, was studied. The variation of the shell features studied, which includedthe shell width, spire height, aperture height and aperturewidth, were found to be related to shell height. Furthermore,significant difference in the shell shape was found not onlybetween the two species but also between males and females ofeach species. (Received 18 August 1983;