The premaxilla is small and forms the inner border of the nostril. There seem to be impressions of small teeth, but no large ones are evident. The nasals are separated by a zigzag suture, and are nearly square. They have the usual relations. The frontals form a portion of the inner boundary of the orbits and unite behind with the parietals, the anterior extensions of which they inclose. The parietals are large elements and together form a broad oval, truncate posteriorly. They inclose between them the pineal foramen in the median suture. It lies in the posterior fourth of the parietals. The postparietals are elongate transversely, and have the usual relations. The pref rental is somewhat triangular and forms the anterior boundary of the orbit. The lacrimal has not been detected. The maxilla is elongate, and with the quadrate jugal forms the exterior border of the cranium. No teeth are observed on the maxilla. The postfrontal and the postorbital form the posterior border of the orbit, and between them inclose the anterior extension of the squamosal. The supratemporal is pointed anteriorly and has the usual relations of that element, joining the postorbital, the postfrontal, the parietal, the tabulare, and the squamosal. The tabulare is larger than the postparietal and is acuminate, the point being inclosed by the squamosal and the supratemporal. The jugal widens fan-shaped posteriorly. It forms a portion of the border of the orbit. The supratemporal, as usual, forms the quadrate angle of the skull. In front of it lies the elongate quadrate jugal. [Illustration: Fig. 22. A. Outline of skull and cranial elements of _Erpetosaurus minutus_ Moodie, from the Cannelton slates of Pennsylvania. Original in U. S. National Museum. × 2. _fr_, frontal; _mx_, maxilla; _par_, parietal; _po_, postorbital; _pp_, postparietal; =pr=, postfrontal; _sq_, squamosal; _spt_, supratemporal; _tab_, tabulare. B. Outline of skull and cranial elements of _Erpetosaurus radiatus_ Cope, from the Coal Measures of Linton, Ohio; partially restored. × 0.75. Original in American Museum of Natural History, _fr_, frontal; _j_, jugal; _mx_, maxilla; _n_, nasal; _or_, orbit; _par_, parietal; _pf_, postfrontal; _po_, postorbital; _pr_, pref rental; _pp_, postparietal; _pmx_, premaxilla; _qj_, quadratojugal; _sq_, squamosal; _spt_, supratemporal; _tab_, tabulare. C. Palate of _Erpetosaurus_ (_tabulatus?_), from the Coal Measures of Linton, Ohio. × 1. American Museum of Natural History, _ex_, exoccipital; _m_, mandible; _mx_, maxilla; _pal_, palatine; _pt_, pterygoid; _prv_, prevomer; _pd_, parasphenoid; _x_, anterior and posterior palatine vacuities.