I.—On Saurosternon Bainii, and Pristerodon McKayi, Two New Fossil Lacertilian Reptiles from South Africa

Extract

Some time since Prof. T. Rupert Jones directed my attention to a curious fossil in the British Museum, obtained by Mr. Bain from Styl Krantz, Sniewe Berg, South Africa. The matrix is of the same nature as that in which the Dicynodonts are so commonly found, and exhibits the greater part of the skeleton, but unfortunately not the skull, of a Lacertilian reptile, not more than seven or eight inches in length. It is represented of the natural size in Plate XI., Fig. 1. The trunk is about two and a half inches long, and appears to have attained hardly more than one-third the length of the tail, which is bent round into three-quarters of a circle, and consists of vertebræ, which are very stout near its root, but become attenuated at its termination (a). The centra of these vertebræ appear to have been slightly constricted in the middle, and are about one-tenth of an inch in length. The anterior caudal vertebræ present strong and long transverse processes. The dorsal vertebræ can hardly have been fewer than eighteen or twenty, and seem also to have possessed hour-glass shaped centre. They are for the most part provided with long curved ribs, the hindermost four or five pair of which become gradually shorter. One of two vertebræ in front of the sacrum may have been devoid of ribs.