The present^-study aimed to elucidate the differences in the mor­phological characteristics of jaw between two land snails, i.e. Eobania vermiculata (Muller). Theba pisana (Muller) and one land slug, i.e. Limax (lams Linnaeus at different ages (juveniles of 2 months old, adults of 9­10 and 20-24 months old) under laboratory conditions. Also, the terato­genic effects of two plant extracts (neem and garlic) and one insect growth regulator (igr), diflubenzuron on jaw of these terrestrial molluscs were investigated. Results indicate that, the morphological features of the jaw were differed considerably according to the terrestrial molluscs species their ages and used either of the two plant extracts or insects growth regula­tor.