The species composition and diversity of molluscas in the Hengyang reaches of Xiang River are studied. There are 42 species belonging to 9 families and 20 are genera. Most of them are representatives of the family Viviparidae and Unionidae. The diversity measurements of molluscas in ten different habitats show that the values of species richness index DMA range from 19.914 to 15.444;species diversity index H' range from 1.327 to 0.953;and evenness indexing Jsw range from 0.955 to 0.836. Based on similarity coefficients C, ten habitats can cluster at the ...