Natural History of the Mammalia of India and Ceylon

by Robert Armitage Sterndale

There are no lower incisors (except in a fossil species), and only two of the molar teeth are to be seen on each side of the jaw at a time, which are pushed out and replaced by others which grow from behind. During the life-time of the animal, twenty-four of these teeth are produced, six in each side of the upper and lower jaws.

The elephant has seven cervical vertebræ, the atlas much resembling the human form; of the thoracic and lumbar vertebræ the number is 23, of which 19 or 20 bear ribs; the caudal vertebræ are 31, of a simple character, without chevron bones.

The pelvis is peculiar in some points, such as the form of the ileum and the arrangement of its surfaces, resembling the human pelvis.

The limbs in the skeleton of the elephant are disposed in a manner differing from most other mammalia. The humerus is remarkable for the great development of the supinator ridge. "The ulna and radius are quite distinct and permanently crossed; the upper end of the latter is small, while the ulna not only contributes the principal part of the articular surface for the humerus, but has its lower end actually larger than that of the radius—a condition almost unique among mammals" (Prof. Flower).

Skeleton of Elephant.

On looking at the skeleton of the elephant, one of the first things that strikes the student of comparative anatomy is the perpendicular column of the limbs; in all other animals the bones composing these supports are set at certain angles, by which a direct shock in the action of galloping and leaping is avoided. Take the skeleton of a horse, and you will observe that the scapula and humerus are set almost at right angles to each other. It is so in most other animals, but in the elephant, which requires great solidity and columnar strength, it not being given to bounding about, and having enormous bulk to be supported, the scapula, humerus, ulna and radius are all almost in a perpendicular line. Owing to this rigid formation, the elephant cannot spring. No greater hoax was ever perpetrated on the public than that in one of our illustrated papers, which gave a picture of an elephant hurdle-race. Mr. Sanderson, in his most interesting book, says: "He is physically incapable of making the smallest spring, either in vertical height or horizontal distance. Thus a trench seven feet wide is impassable to an elephant, though the step of a large one in full stride is about six and a half feet."

The hind-limbs are also peculiarly formed, and bear some resemblance to the arrangement of the human bones, and in these the same perpendicular disposition is to be observed; the pelvis is set nearly vertically to the vertebral column, and the femur and tibia are in an almost direct line. The fibula, or small bone of the leg, which is subject to great variation amongst animals (it being merely rudimentary in the horse, for instance), is distinct in the elephant, and is considerably enlarged at the lower end. The tarsal bones are short, and the digits have the usual number of phalanges, the ungual or nail-bearing ones being small and rounded.

A. Muscles of Elephant's Trunk. B. Cross-section of ditto.