extijS'ct batrachia. 397 



are in the middle of the skull. The outline of the muzzle in our species 

 is then broad, rounded, as in the Menopoma Allegheniense, while in the lat- 

 ter it is ovate and produced. It therefore resembles also in its propor 

 tions the genus Herpetocephalus, Huxl., from the Irish Coal Measures. 



The parietal bones extend to opposite the posterior margins of the or- 

 bits, are then gradually contracted, and form an acuminate prolongation 

 on each side the wedge-shaped frontals. The prefrontals are thickened 

 on each side the front, behind the external nares. The sutures defining 

 the frontals anteriorly, the nasals and the premaxillaries behind can not 

 be made out. The median longitudinal suture is a marked and zigzag 

 one, and can be seen as far posteriorly as the anterior margin of the or- 

 bits. The external nostrils are large, and opposite the inner margin of 

 the orbit on each side. This separation of the nares is associated with a 

 greater transverse extent of premaxillaries than in some of the species. 

 These have been set with numerous teeth, judging by their small im- 

 pressions ; no larger ones have left traces, and no traces of any on the 

 maxillaries. 



A fragment of mandible remains, but without teeth or external sur- 

 face. It shows a large internal (dental) canal. 



Total length of cranium, 25.5 lines; with do. 3 lines behind orbits, 

 24.0; do. do. between orbits, 7.5 ; do. do. between nares, 5.0; do. do. beween 

 occipital condyles, 2.2; do of supraoccipital bone, 6.0; do. of right parie- 

 tal, 6.0; extent of premaxillaries, 8.7 ; length of orbit, 6.0. 



This species differs from the Tuditanits radiatus in the larger and more 

 posteriorly placed orbits. 



TuDiTANUs HuxLEYi, Cope. 



Transactions American Philosophical Society, April, 1874. 



Represented by a considerable portion of the face and muzzle of a 

 single individual. A portion of the left mandible, supporting three 

 teeth, remains in place, and almost the entire boundary of the right orbit 

 is preserved. 



The fragment indicates a much larger species than any other referred 

 to the genus, and, next to the Leptophradus obsoletus, the largest of the 

 Batrachians of the Ohio Coal Measures. Without more complete remains, 

 it is not easy to determine its generic relations finally. 



The form of the head is probably elongate, and the muzzle neither 

 very obtuse nor elongate. The orbit is rather small, and near the mid- 



