Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Zoology

The present study gives special focus on development of sense organs of the Montpellier snake, Malpolon monspessulana (Colubridae, Squamata). Embryos of different developmental stages were extracted from eggs and subjected to the traditional protocol of preparation of permanent histological microscopical slides. Selected sections of the nose, eye, middle ear and membranous labyrinth regions were photographed. The olfactory apparatus develops as an ectodermal olfactory placode, which transforms into an olfactory pit that finally to an olfactory canal. The latter differentiates into the fully formed olfactory organ. The ophthalmic apparatus has two sources of origin; the optic cup, which arises from the lateral wall of the prosencephalon, and the lens, which arises from a lens placode of the ectoderm opposite to the optic cup. The optic cup gives rise to all parts of the eye except the lens. The middle ear is only represented by a rod-shaped structure, which is the columella auris .The stylohyal chondrifies and fuses with the well-organized quadrate. The membranous labyrinth arises as an otic placode of the ectoderm, which transforms into an otic pit that finally organized into a fully formed inner ear including the anterior, posterior and horizontal semicircular canals, utriculus, sacculus and lagena

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