Fig. 4

Artiodactyl forefeet. a Pig, b deer, c camel, showing paraxonic symmetry characteristic of even-toed ungulates, where the digits are symmetrical across a plane between digits 3 and 4. Pigs and deer show “true cloven hoofs”, while camels walk on their digits and do not show true cloven hoofs. Original image public domain, from Flower, 1885, An Introduction to the Osteology of the Mammalia