Mitotic and meiotic chromosome preparations ofBellamya bengalensisf.doliaris(Viviparidae),Pila globosa(Pilidae) andCyclophorus polynema(Cyclophoridae) were made by colchicine—ovotestis cell suspension—methanol acetic acid—flame drying—Giemsa technique. Karyotypes were prepared on the basis of decreasing length of the chromosomes and their morphometric analyses were done. The diploid number 2n= 22 with the chromosome formulan= 7m + 4 sm and FN = 44 forBellamya bengalensisf.doliaris, 2n= 28 with the chromosome formulan= 9m + 5sm and FN = 56 forPila globosaand 2n= 28 with the chromosome formulan= 13m + 1sm and FN = 56 forCyclophorus polynemawere obtained. Chromosome numbers of each species was confirmed from the respective metaphase-I spreads and behaviour of their meiotic chromosomes were studied. The data obtained for each species were compared with the available chromosomal information on other confamilial species and the role of the possible mechanisms of karyotypic evolution in them have been discussed. Conservativeness with regard to chromosomal change at higher taxon level has been discussed.