Pedagogy of Biological Science (Part II ) - Structural organism of animals, Structural organism of animals, Pedagogy of Biological Science, B.Ed., II Year, Pedagogy, X science, Samacheer kalvi science, Biology, Indian cattle leech, habit and habitat, External morphology, divisions of body, body wall, locomotion, Digestive system, segmentation of leech, circulatory system, Nervous system, urinogenital system,