Reptiles have dry and thick skin to protect them from drying out, as well as claws made from modified skin. Except for crocodiles, which have a four chambered heart, reptiles have a tree chambered heart. They have well developed kidneys and lungs, and excrete uric acid. They have a full digestive system and have an internal bone structure. They have chemoreceptors, vibration senses, heat senses, eyes and a sense organ called Jacobson's organ that tells the reptile about its surroundings.
Reptiles are ectothermic.
They have an amniotic egg with a leathery shell protecting it, a yolk with nourishment for the embryo, a chorian for gas exchange and an allentois for waste removal. Turtles have a two part shell, with the vertebrae and rib fused to it. Dinosaurs were a member of class reptilia. Class aves are the birds. They have claws and scales on their feet, and also have an amniotic egg, with a brittle shell, that is incubated in a nest.