; subclass Archosauria, order Crocodilia)
A family of crocodilians in which the fourth tooth of the lower jaw fits into a notch in the upper jaw, being visible when the mouth is closed. Crocodylus niloticus (Nile crocodile) basks on river banks and may draw its legs beneath its body in order to move rapidly on land; it occurs throughout central and southern Africa and Madagascar, although it is now rare due to hunting. Crocodiles sometimes exceed 6 m in length. C. porosus (salt-water crocodile or estuarine crocodile), found from India to northern Australia, tolerates salt water and swims in the open sea; it has ridges from the eyes along the length of the snout and salt-secreting glands around the eyes. The false gharial (Tomistoma schlegeli) has been shunted back and forth between the Crocodylidae and the Gavialidae and its affinities are still obscure; there is even a view that the true gharial should be included in the Crocodylidae. There are 13 species in the family, occurring in fresh, brackish, and salt water in the Old and New World tropics.