Richard Lydekker

“ On the other hand in the Diplarthra, the group to which the vast majority of modern Ungulates belong, the second or lower row has been shifted altogether towards the inner side of the limb, so that the magnum is brought considerably into relation with the scaphoid, and is entirely removed from the cuneiform, as in most existing mammals.
In the typical Ungulata or Diplarthra, the feet are never plantigrade, and the functional toes do not exceed four—the inner digit being suppressed, at all events in all forms which have existed since the Early Eocene period. ”

“ All the existing members of the group are eminently adapted for a terrestrial life, and in the main for a vegetable diet. Though a few may in some circumstances kill living creatures smaller than themselves for food, none are habitually predaceous. ”

“ There is never an os penis. The uterus is bicornuate. The teats are usually few, and inguinal, but may be numerous and abdominal (as in Suina) , although they are never solely pectoral. The cerebral hemispheres in existing Ungulates are well convoluted. ”