FIG. 66. CERVICAL VERTEBRA OF ORNITHODESMUS
From the Wealden Beds of the Isle of Wight
The Wealden strata being shallow, fresh-water deposits might have been expected to supply better knowledge of Pterodactyles than has hitherto been available. Jaws of Ornithocheirus sagittirostris have been found in the beds at Hastings, and in other parts of Sussex. Some fragments are as large as anything known. The best-preserved remains have come from the Isle of Wight, and were rewards to the enthusiastic search of the Rev. W. Fox, of Brixton. In the principal specimen the teeth were short and wide, the head large and deep with large vacuities, but the small brain case of that skull is bird-like. The neck bones are 2½ inches long. In the upper part of the back the bones are united together by anchylosis, so that they form a structure in the back like a sacrum, which does not give attachment to the scapula, as in some Pterodactyles from the Chalk, but the bones are simply blended, as in the frigate-bird, allied to Pelicans and Cormorants. And then after a few free vertebræ in the lower part of the back, succeeds the long sacrum, formed in the usual way, of many vertebræ. I described a sacrum of this type from the Wealden Beds, under the name Ornithodesmus, referable to another species, which in many respects was so like the sacrum of a Bird that I could not at the time separate it from the bird type. This genus has a sternum with a strong deep keel, and the articulation for the coracoid bones placed at the back of the keel in the usual way, but with a relation to each other seen in no genus hitherto known, for the articular surfaces are wedge-shaped instead of being ovate; and instead of being side by side, they obliquely overlap, practically as in wading birds like the Heron. I have never seen any Pterodactyle teeth so flattened and shaped like the end of a lancet; and from this character the form was known between Mr. Fox and his friends as "latidens." The name Ornithodesmus is as descriptive of the sternum as of the vertebral column. The wing bones, as far as they are preserved, have the relatively great strength in the fore limb which is found in many of the Pterodactyles of the Cretaceous period, and are quite as large as the largest from the Cambridge Greensand. In the Sussex species named P. sagittirostris the lower jaw articulation was inches wide.
FIG. 67. STERNUM OF ORNITHODESMUS
Showing the overlapping facets for the coracoid bones (shaded) behind the median keel
FIG. 68. FRONT OF THE KEEL OF THE STERNUM OF ORNITHODESMUS LATIDENS
Showing also the articulation for the coracoid bone
