original 1884 description, assumed that this digit was lost in Ceratosaurus, but Charles Gilmore, in his 1920 monograph, noted an attachment area on the second metatarsal demonstrating the presence of this digit. Uniquely among theropods, Ceratosaurus possessed small, elongated, and irregularly formed osteoderms (skin bones) along the midline of its body. Such osteoderms have been found above the neural spines of cervical vertebrae 4 and 5, as well as caudal vertebrae 4 to 10, and probably formed a continuous row that might have extended from the base of the skull to most of the tail. As suggested by Gilmore in 1920, their position in the rock matrix likely reflects their exact position in the living animal. The osteoderms above the tail were found separated from the neural spines by to , possibly accounting for skin and muscles present in between, while those of the neck were much closer to the neural spines. Apart from the body midline, the skin contained additional osteoderms, as indicated by a by large, roughly quadrangular plate found together with the holotype; the position of this plate on the body is unknown. Specimen UMNH VP 5278 was also found with a number of osteoderms, which have been described as amorphous in shape. Although most of these were found at most 5 m apart from the skeleton, they were not directly associated with any vertebrae, unlike in the C. nasicornis holotype, so their original position on the body cannot be inferred from this specimen. Classification In his original description of the Ceratosaurus nasicornis holotype and subsequent publications, Marsh noted a number of characteristics that were unknown in all other theropods known at the time. Two of these features, the fused pelvis and fused metatarsus, were known from modern-day birds, and according to Marsh, clearly demonstrate the close relationship between the latter and dinosaurs. To set the genus apart from Allosaurus, Megalosaurus, and coelurosaurs, Marsh made Ceratosaurus the only member of both a new family, the Ceratosauridae, and a new infraorder, the Ceratosauria. This was questioned in 1892 by Edward Drinker Cope, Marsh's rival in the Bone Wars, who argued that distinctive features such as the nasal horn merely showed that C. nasicornis was a distinct species, but were insufficient to justify a distinct genus. Consequently, he assigned C. nasicornis to the genus Megalosaurus, creating the new combination Megalosaurus nasicornis. Although Ceratosaurus was retained as a distinct genus