NO. 1796. A NEW LABYRI^'THODONT FROM KANSAS— MOODIE. 491 



ERPETOSUCHUS, ne^^^ genus. 



The genus is very readil}^ distinguished by two prominent charac- 

 tere: The short uniform dentition and the presence of two elongate, 

 oval, internal mandibular formina on the inner side of the jaw. The 

 genus may be further distinguished by the great depth of the posterior 

 portion of the jaw and the slender anterior part as well as by 

 the ornamentation, which is typically the rough tuberculated laby- 

 rinthodont sculpture on the anterior end of the mandible. This 

 changes gradually to longitudinal grooves and ridges of a rather 

 small size on the posterior portion, a very unusual arrangement for a 

 labyrinthodont. 



These characters are sustained by those of the skull fragment, in 

 which the dentition is uniform and the sculpture very similar to that 

 of the mandible. The ribs are long, curved, and solid as in other 

 labyrinthodonts. 



The genus receives its name from the similarity of the internal 

 surface of the jaw to that of the crocodiles and alhgatoi-s of the present 

 day. 



{kpn£xbv=di. creeping thing; aotyjof = crocodile.) 



ERPETOSUCHUS KANSENSIS, new species. 



The species is represented in the collection of the U. S. National 

 Museum by a fragment of a skull, with portions of two ribs (Cat. No. 

 6699, Vert. Pal. U.S.N.M.) and the larger part of the left ramus of 

 the mandible (Cat. No. 6680, Vert. Pal. U.S.N.M.). The mandible 

 was preserved in a large block of coal which contained the impression 

 of the back portion of the mandible from which the bone had been 

 weathered. It was possible to remove the bone and make a plaster 

 cast of the impression. This shows in a very satisfactory manner all 

 the characters of the external surface. 



SKULL. 



Only a portion of the left maxilla, with fourteen teeth, and a part of 

 the nasal are preserved. The skull seems to have been flattened 

 sideways and the right side of the skull has been crushed flat under 

 the left. It has not seemed feasible to remove the skull from the 

 matrix. 



The teeth are umform, rather short, bluntly conical, curved back- 

 ward, and coarsely striate. They are somewhat crowded, the bases 

 being separated from each other by only a fraction of a millimeter. 



The maxilla and portion of the nasal are coarsely sculptured with 

 elongate pits and ridges. A portion of the infraorbital lateral line 

 canal is preserved. It is simply a rounded groove with three short 

 branches. It Kes near the middle of the maxilla (fig. 1). 



