1/7 CHAPTER VI. The bony core sutured to the front of the upper and lower jaws was covered in life by a horny sheath, as in birds or turtles. But this is not the only feature in which they came nearer to birds than do the other Dinosaurs. The pelvic or hip bones are much more bird-like in many respects, especially the backward direction of the pubic bone, the presence of a prepubis, in the number of vertebrae coossified into a solid sacrum, in the proportions of the ilium and so on. Various features in the anatomy of the head, shoulder-blades and hind limbs are equally suggestive of birds, and it seems probable that the earliest ancestors of the birds were very closely related to the ancestors of this group of Dinosaurs. |