Structure and Appearance

Birds are thought to have descended from Triassic Theropods which were already fairly bird-like. They had a bipedal gait and a hollow bone structure similar to that of modern birds.

Scientific American, Feb. 1998

Archaeopteryx seems to be the intermediate form between reptiles and birds. It is often cited as a classic example of a "missing link," and in the Victorian tradition of such important elements in traditional and gradualistic evolutionary progress, it is seen as "half reptile and half bird."