The proportions of the mandible, as maybe judged from the table of measurements, are rather stout and the teeth are strong and numerous. There are evidences of 19 teeth preserved. The sutures separating the articular (_art_), angular (_ang_), surangular (_sa_), coronoid (_cor_), and the dentary (_d_) (fig. 22, F) are clear for at least the greater part of their length and they may be easily restored for the remainder of their course. The surangular is thus seen to rival the dentary in size and on it occurs the peculiar sculpturing which approximates so closely that on the skull of _Erpetosaurus tabulatus_ Cope. The presence of the long anterior tooth is strikingly characteristic of many Microsauria. It is well developed in _Sauropleura longidentata_ Moodie and _Sauropleura (Anisodexis) enchodus_ Cope. It is also present in well-developed form in the later labyrinthodonts. The teeth are all, with the exception of the fourth from the anterior end, rather short, curved, and sharply pointed, with an indication of longitudinal fluting. The arrangement of the mandibular elements recalls in a striking way the mandible of _Eryops megacephalus_ Cope as figured by Branson (49). Measurements of the Mandible Provisionally Associated With Erpetosaurus tabulatus Cope. (No. 8542 G, American Museum of Natural History.) mm. Length of mandible 32 Posterior width across surangular 6 Width of dentary 3 Width of jaw at tip 1.5 Length of one of the posterior teeth 1.25 Width across base of same tooth .50 Length of long anterior tooth 2 Width of same tooth at base .75 Another specimen of this same species is 8550 G, of the American Museum. Linton, Ohio, Coal Measures. PALATE OF ERPETOSAURUS TABULATUS COPE. Moodie, Bull. Amer. Mus. Nat. Hist., XXVI, pp. 352-354, pl. lxi, fig. 2, 1909. The specimen is half a cranium with its impression. It is referred to _Erpetosaurus_ on the basis of the sculpturing of the mandible and the posterior table of the skull. On the surangular there is seen the rugosity which is common to other members of the genus. The characters presented are those of _Erpetosaurus tabulatus_ Cope, but the reference is rather uncertain. The specimen is unique among the known American material in showing the structure of the palate. Jaekel (347) has figured and described the palate of _Diceratosaurus punctolineatus_ Cope from the Linton beds. The present palate differs from that species only in the enlarged ectopterygoid and the smaller palatine.