Class reptilian (L. Reptilia= creeping) includes animals which are cold blooded.
2) The skin has a few cutaneous glands and high levels of keratin, which prevents water loss through the skin.
3) The scales and scutes are formed from the epidermis and are also made of keratin, to protect the body.
4) Reptiles are considered as tetra pods with two sets of paired limbs. Most of these animals have five clawed toes on each limb.
5) All reptiles have spinal columns and a strong skeletal system with a rib cage. They have a well-developed brain and a central nervous system.
6) Unlike amphibians, reptiles do not pass through an embryonic stage with gills. These animals breath with well-developed lungs, right from birth. Most of them have two lungs, except some snakes.
7) All reptiles have three-chambered hearts, except crocodiles, which have four-chambered hearts (2 atria, 2 ventricles), like mammals and birds.
8) Reptiles have a digestive system which has a muscular opening at the base of the tail.