Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/129

 Rh

From the enormous width of the pelvis, it follows also that the abdominal cavity was extremely large, and the viscera voluminous, and adapted to the digestion of vegetable food.

The form and proportions of the thigh bone, (v) are not less extraordinary than those of the pelvis, being nearly three times the thickness of the femur of the largest Elephant. Its breadth is nearly half its entire length, and its head is united to the body of the bone by a neck of unusual shortness and strength, twenty-two inches in circumference. Its length is two feet four inches, and its circumference at the smallest part two feet two inches; and at the largest part, three feet two inches. Its body is also flattened; and by means of this flatness, expanded outwards to a degree of which Nature presents no other example. These peculiarities in the femur appear to be subservient to a double purpose: first, to give extraordinary strength by the shortness and solidity of all its proportions; and secondly, to afford compensation by its flatness outwards; for the debility which would otherwise have followed from the inward position of the sockets, (t,) by which the femur, (u,) articulates with the pelvis.

The two bones of the leg (x, y,) are also extremely short, and on a scale of solidity and strength, commensurate with that of the femur that rests upon them. This strength is much increased by their being united at both extremities; a union which is said by Cuvier to occur in no other animals except the Armadillo and Chlamyphorus; both of which are continually occupied in digging for their food.

The articulation of the leg with the hind foot is admirably contrived for supporting the enormous pressure of downward weight; the astragalus (z,) or great bone of the instep, being nine inches broad and nine inches high, is in due proportion to the lower extremity of the tibia, or leg bone, with which it articulates; and rests upon a heel bone, of the extraordinary length of seventeen inches, with a circumference of