Reptilas are represented by lizards, snakes, turtles, tortoises, alliga-tors, crocodiles and the tuatara lizard, Sphenodon punctatuni. The tetrapods like reptiles, birds and mammals are referred to as amniotes. The amniotes have certain membranes associated with embryos inside the egg. It is an adaptation in terrestrial forms during development.
The body of Reptilia is variable in shape. It is covered with an exoskeleton of horny imbricate epidermal scales. Skin glands are practically absent. The limbs are of pentadactyl type adapted for climbing, running and paddling. The en-doskeleton is well ossified. Respiration is by lungs. The heart is three cham-bered (In crocodiles it is four chambered). The functional kidney of the adult are metanephros. The Sexes are separate. Fertilization is internal. The eggs are covered with leathery shells. Reptiles have developed some form of copu-latory organ to transfer the sperms into the cloaca of the female.
Example: Garden lizard, Cobra, Monitor lizard, Crocodile, Turtle.