The Ornithosauria / An elementary study of the bones of Pterodactyles made from fossil remains found in the Cambridge Upper Greensand, and arranged in the Woodwardian Museum of the University of Cambridge

by H. G. Seeley

The sternum is compared with the sternum of the birds Apteryx and Aptenodytes, is stated to be formed, in the main, on the Ornithic type, and to possess distinct synovial articular cavities for the coracoids such as only occur in birds. The inter-coracoid process of the sternum is compared with that of Bats, Birds, and Crocodiles.

The mechanism of the framework of the wings is said to be much more bird-like than bat-like, the anchylosed scapula and coracoid being remarkably similar to those of a bird of flight. The coracoid is shorter and straighter in birds than in Pterodactyles, but no comparisons are made with reptiles.

The humerus is known only by the proximal end. It is said to conform at its proximal end more with the Crocodilian than with the Avian type, but to have the radial crest much more developed than in either Crocodile or Bird. The bone is, however, chiefly compared with birds, and is figured between corresponding bones of a Vulture and a Crocodile. The pneumatic texture is said to be as well marked as in any bird of flight.

Of the carpus it is said, the Pterodactyle, in the complete separation of the metacarpus from the antibrachium by two successive carpals answering to the two rows, adheres more closely to the reptilian type than to that of birds. But the row which was regarded as proximal is the distal row, while the supposed distal row is proximal.

The claw-phalange and distal end of the wing-metacarpal, the mandible, teeth, and jaw are the other bones described, but their comparative osteology is not discussed. In the Professor's account of a fragment of a jaw it is said, "The evidence of the large and obviously pneumatic vacuities now filled with matrix, and the demonstrable thin layer of compact bone forming their outer wall, permit no reasonable doubt as to the Pterosaurian nature of this fossil. All other parts of the flying reptile being in proportion, it must have appeared with outstretched pinions like the soaring Roc of Arabian romance, but with the demoniacal features of the leathern wings with crooked claws, and of the gaping mouth with threatening teeth, superinduced."

When the specimens on which Prof. Owen had founded the foregoing views of the osteology and classification of these animals were at length returned to the Woodwardian Museum, it became a duty of the present writer to arrange and name them. And in a Memoir on Pterodactyles which was communicated to the Cambridge Philosophical Society and read March 7 and May 2 and 16, 1864, a position was claimed for them, distinct from reptiles, as a separate sub-class of Sauropsida, nearly related to birds.

In September of the same year a communication was made to the British Association "On the Pterodactyle as evidence of a new sub-class of vertebrata (Sauromia)," with enlarged drawings of the skull and some of the other bones, in which the conclusions arrived at were that, excepting the teeth, there is little in such parts of the head as are preserved to distinguish the Cambridge Pterodactyles from birds; and that the remainder of the skeleton gives a general support to the inference from the skull.

Papers were communicated to the Cambridge Philosophical Society on February 17, 1868, on indications of Mammalian affinities in Pterodactyles in the pelvis and femur, and February 22, 1869, on the bird-like characters of the brain and metatarsus in the Pterodactyls from the Cambridge Greensand. The other references to Cambridge specimens are in a paper "On the literature of English Pterodactyles" in the Annals and Magazine of Natural History for Feb. 1865, and in "An epitome of the evidence that Pterodactyles are not reptiles, but a new sub-class of vertebrate animals allied to birds," in the same magazine for May, 1866.

In the meantime Prof. Owen's views have somewhat changed. In the first volume of the Comparative Anatomy and Physiology of the Vertebrata (1866), the Pterosauria are classed as the highest group of reptiles, and take rank above the Dinosauria. In the second volume of that work (1866), occurs the following passage:

"Derivatively the class of birds is most closely connected with the Pterosaurian order of cold-blooded air-breathers. In equivalency it is comparable rather with such a group than with the Reptilia in totality, or with the Mammalia."