Class Reptilia

Class Reptilia (Latin repere = to creep or crawl) includes animals such as Naja naja (cobra), Hemidactylus (wall lizard), Chelonia (turtle), Crocodilus (crocodile), Testudo (tortoise), chameleon (tree lizard), Bangarus (krait) and Vipera (viper).

Reptiles are the first truly terrestrial vertebrates, though a few are aquatic or semi-aquatic, and some are found in marshy areas. Locomotion typically occurs using pentadactyl (five-digit) limbs bearing claws, which the animal uses to walk or creep; snakes, by contrast, are limbless and crawl on their belly.

Reptiles are poikilothermic. The skin is dry and non-glandular, covered by an exoskeleton of epidermal scales, scutes, shields or plates; lizards and snakes shed this skin periodically. A tympanum is present. The heart has two complete auricles, but the ventricles are incompletely partitioned, so the heart is not perfectly four-chambered — crocodile is the notable exception, having a nearly complete division of the ventricle. …