Progression of Animals (or On the Gait of Animals; Greek: Περὶ πορείας ζῴων; Latin: De incessu animalium) is one of Aristotle's major texts on biology. It gives details of gait and movement in various kinds of animals, as well as speculating over the structural homologies among living things.Aristotle sets out to "discuss the parts which are useful to animals for their movement from place to place, and consider why each part is of the nature which it is, and why they possess them, and further the differences in the various parts of one and the same animal and in those of animals of different species compared with one another" (704a1-4). Progression of Animals illustrates Aristotle's teleological approach to animal biology. Source: Wikipedia (en)