Abstract: | A comparative study has been made of the dimensional characteristics in six species of Muridae (Malardia meltada, Bandicota bengalensis, Albino rat, Rattus norvegicus, Mus booduga, Rattus rattus). Characteristic differences were found in the dimensions of their spermatozoa. Head dimensions viz., acrosome length, width, area and post-acrosomal area, vary significantly between different species but the differences are significant within individuals of the same species. Flagellum dimensions viz., mid-piece length, breadth, area and main-piece length also vary significantly between different species; within individuals of the same species the differences are not significant except for mid-piece breadth, which varies significantly both between and within the species. The ratio of flagellum to head varies significantly between species but the difference is not significant within individuals of the same species. The significance of the variabilities is discussed. |