THE COAL MEASURES AMPHIBIA OF NORTH AMERICA. 



The internal surface of the mandible shows much similarity to that of the croco- 

 diles and alligators of the present day. The resemblance is not due to homology of 

 structures, but must be regarded as a parallel development of similar characters. 



Eobaphetes kansensis Moodie. 

 MOODIE, Proc. U. S. Nat. Mus., 39, pp. 491-494, figs, i to 3, 1911 (Erpetosuchus). 



Type: Specimen No. 6699, U. S. National Museum. 



Horizon and locality: Coal Measures of Washington County, Kansas. 



The species is represented in the collections of the U. S. National Museum by a 

 fragment of the skull, with portions of two ribs (Cat. No. 6699, Vert. Pal. U. S. 

 Nat. Mus.) and the larger part of the left ramus of the mandible (Cat. No. 6680, 

 Vert. Pal. U. S. Nat. Mus.). 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 of the char- 

 acters of the external surface. 



Skull. Only a portion of the left maxilla, with 14 teeth, and a part of the nasal 

 are preserved. The skull seems to have been laterally crushed 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 uniform, rather short, bluntly conical, curved backward, 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 lies near the middle of the maxilla. 



Mandible. It has been possible to study both sides of the mandible. The 

 left ramus was preserved in the coal, with its inner face exposed. This face is broken 

 by two large oval openings, the internal mandibular foramina. This is the term 

 used by Reynolds for the openings on the inner surface of the alligator jaw. So 

 far as I can ascertain, no other known labyrinthodont mandible displays this char- 

 acter in such a marked degree. Dr. Branson has figured in Anaschisma. browni 

 Branson from the Triassic (49) of Wyoming the inner surface of the left ramus, on 

 which there are likewise two openings but differently situated. A similarity be- 

 tween the two mandibles is observed in that the suture separating the prearticular 

 and angular touches the posterior edge of the posterior foramen. 



Several of the sutures are well preserved and they have been indicated in the 

 drawing (fig. 42). The pillar separating the two foramina is cut by the suture 

 separating the angular and prearticular very much as in Anaschisma, with the 

 difference that in the latter form the angular and prearticular are not approximated. 

 I believe I detect the suture as represented separating the anterior end of the angular 

 from the dentary and splenial. I am assured of the portion near the anterior fora- 

 men and also of the part near the tip of the ramus. This shows the angular to be a 

 very elongate element, running very nearly the entire length of the mandible, much 



