Perissodactyla :: Perissodactyla (n. pl.) A division of ungulate mammals, including those that have an odd number of toes, as the horse, tapir, and rhinoceros; -- opposed to Artiodactyla..
Tetradactylous :: Tetradactylous (a.) Having, or characterized by, four digits to the foot or hand..
Thecodactyl :: Thecodactyl (n.) Any one of a group of lizards of the Gecko tribe, having the toes broad, and furnished with a groove in which the claws can be concealed..
Zygodactylae :: Zygodactylae (n. pl.) The zygodactylous birds. In a restricted sense applied to a division of birds which includes the barbets, toucans, honey guides, and other related birds..
Zygodactylous :: Zygodactylous (a.) Yoke-footed; having the toes disposed in pairs; -- applied to birds which have two toes before and two behind, as the parrot, cuckoo, woodpecker, etc..