Of blooded and viviparous quadrupeds some have the foot cloven into many parts, as is the case with the hands and feet of man (for some animals are manytoed, as the lion, the dog, and the leopard); others have feet cloven in two, and instead of nails have hooves, as the sheep, the goat, the deer, and the hippopotamus; others are uncloven, such for instance as the solid hooved animals, the horse and the mule.