Specimens of Archaeopteryx resembling a flying squirrel. After conducting an embryological comparison with modern birds, he noticed a similarity between "Archaeopteryx" and the embryonic stage of birds, concluding that the former was likely an "archetype", or created kind, of the bird lineage. Owen's monograph presented a description of the osteology and the plumage, though he missed a number of elements. Owing to its overall similarity to the structure of modern birds, Owen postulated a toothless, horny beak-like instrument "fitted for preening", and misinterpreted the fragment of an upper jaw with teeth, located next to the pelvis on the specimen, as the remains of
Specimens of Archaeopteryx a fish. Fragments of the braincase and upper jaw were later identified and published by other researchers. While Owen's 1863 monograph on the specimen is historically considered to be the first real description of "Archaeopteryx", Henry Woodward, assistant of the Geological Department of the British Museum, had published a shorter article on the specimen in December 1862. Here he provided a detailed description as well as the first published illustration of the specimen, sketched from the original. Rather than an attempt to steal Owen's glory, Woodward gave him due credit in this article as its official describer. Woodward's article nevertheless