100 THE COAL MEASURES AMPHIBIA OF NORTH AMERICA. 



gate, and with the quadratojugal 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 quadratojugal. 



Dendrerpeton is not well enough known for an exact comparison with Erpeto- 

 saurus obtusus, but Cope separated the latter from Dendrerpeton on the position of 

 the orbits and the broadly rounded muzzle. This species differs from the other 

 species of the genus in the form of the cranium, as well as in the characters which 

 separate it from Dendrerpeton. 



MEASUREMENTS OF THE TYPE OF ERPETOSAURUS OBTUSUS COPE. 



mm. mm. 



Median length of the skull 48 Width of orbit 7 



Width of skull at posterior border 56 Interorbital space 15 



Width across orbits 37 Diameter of nostril 1.5 



Length of orbit 12.5 Diameter of pineal foramen 1.75 



Two other specimens, Nos. 8602 G and 8608 G of the American Museum, are 

 associated in this species. 



Erpetosaurus tabulatus Cope. 



COPE, Proc. Amer. Phil. Soc., xvi, p. 577 (Tudilanus tabulatus). 



MOODIE, Jour. Geol., 17, p. 52, figs. 8, 9, 1909. 



MOODIE, Bull. Amer. Mus. Nat. Hist., xxvi, pp. 347, 351, pi. 59, fig. 2; pi. 62, fig. 2, 1909. 



Type: Specimen in the Zoological Collection of Columbia University. 



Horizon and locality: Linton, Ohio, Coal Measures. (Plate 25, fig. 2.) 



The species is known from a single well-preserved skull and its obverse in the 

 collection of Columbia University in New York City. I am indebted to Dr. Bash- 

 ford Dean for the privilege of studying this interesting form. It is from the Linton 

 deposits of Ohio. The remains include a nearly complete cranium and a complete 

 clavicle of the right side. The species agrees in all essential respects with the char- 

 acters of the genus Erpetosaurus, presenting a broad, flat head and a triangular 

 clavicle. 



The cranium is wider than long, the muzzle broadly rounded. The orbits are 

 wide ovals, and their posterior borders fall little behind the transverse line dividing 

 the skull equally. The interorbital width equals the long diameter of the orbit. The 

 posterior outline of the cranium is truncate in a straight transverse line between the 

 prominent tabulare angles. The composition of the cranium is different from that of 

 any other species of Erpetosaurus in the large size of the tabulare and the fact that 

 the supratemporal is excluded from the parietal by the extension of the postorbitals 

 and the tabulare. This may be a generic character and entitles the species to be 

 placed in a new genus, but it will be retained here until more of the anatomy of the 



