EXTINCT BATRACHIA. 389 



rior prolongation, which is obtuse, and rises at once into the coronoid 

 process. Teeth on this dentary, seven ; the same number is on the pre- 

 served ramus ; this number is suspected to be complete, or- nearly so. 

 The teeth terminate at the obvious termination of each ramus, which is, 

 it is true, slightly obscured. These teeth are the longest of the Micro- 

 sauria in relation to the depth of the ramus, equaling the largest in 

 Oestocephalus. They are doubtless exposed, as are some of those of the 

 last named genus, by the splitting away of the outer parapet of the den- 

 tary bone. As no traces of alveoli have been thus rendered visible, I 

 suspect the dentition to have been acrodont, as in some existing 

 Batrachia. 



No external surface of the mandible remains, but there are no im- 

 pressions of sculpture on the matrix. A little external face of the pre- 

 maxillary displays none. 



Preserved length of ramus (imperfect), 11 lines; depth at last tooth, 

 2 ; length of exposed tooth, 1.7 ; do. of dentary, 7.5 ; depth at coronoid, 

 3.5 ; do. at first tooth, 1.3. 



In the mandibular ramus of the Hylerpeton Dawsonii there are, accord- 

 ing to Prof. Owen, at least nine teeth; in the present species there are 

 but seven. Prof. Owen's plate indicates a ramus whose depth at the last 

 tooth enters eight and a half times the total length. In our species this 

 depth enters about five times. 



This species is dedicated to Prof. John S. Newberry, the able director 

 of the Geological Survey of Ohio, and discoverer of most of the Batrachia 

 herein described. 



Pelton, Wyman. 



Proceed. Acad. Nat. Sci., Phila., 1868^ p. 211 ; Trans. American Philos. Soc, 1869, 9. 

 Raniceps, Wyman ; Amer. Jour. Sci. and Arts, 1858, p. 158 ; not of Cuvier (Pediculati). 



Three genera are here indicated as pertaining to a lacertiform type of 

 Stegocephali. In one of these there are abdominal chevrons and no 

 thoracic shields (Sauropleura); in another (Tuditanus) no abdominal 

 chevrons and thoracic shields present. These genera are doubtless well 

 defined, but one or the other of them may be identical with Pelion. The 

 only specimen of the only species of the latter exhibits an inferior view 

 of a portion of the skeleton ; and the obverse, on which the thoracic and 

 abdominal armor could have been preserved, has not come under my ob- 

 servation. The specimen, however, does not exhibit any ribs, although 

 the vertebrae are well preserved; in the two genera above mentioned, 

 well-developed ribs are presented. 



