Characteristics of class Reptilia: 1. Creeping and burrowing terrestrial animals with scales on their body, skin is dry, and rough, without any glands. 2. Cold-blooded animals; exhibit a meroblastic segmentation. 3. Few of these shed the scales on their skin as skin cast. 4. Respiration by lungs. 5. Two pairs of pentadactyl limbs, each bearing claws. Snakes are an exception. 6. Heart is 3 chambered. However, crocodiles have a 4-chambered heart. 7. Nervous system comprises of 12 pairs of cranial nerves, lateral line system is absent. 8. Except for snakes, all the reptiles have well-developed ears. 9. possess a typical cloaca. 10. Reptiles are ureotelic, uricotelic, and ammoniotelic. 11. Fertilization is internal; oviparous and the eggs are very yolky