K9Pi 



1878.] OAi. [Cope. 



ing the maxillaries in size within the latter, perhaps on the palatine bone. 

 No row of smaller teeth within the maxillary series, or on the vomer, as in 

 Mastodonsaurus and Gapitosauras. The choanal are large, and extend 

 well forwards. 



This species is the most abundant as well as the largest Batrachian of the 

 formation. Some of the crania are .500 Ms. in length. 



It may be added that the vertebrae which I described (1. c.) under the 

 head of this species, and which were found with the cranium which repre- 

 sents it, may not really belong to it. 



Parioxys ferricolus. Gen. et sp. nov. 



Char. Genericus. Suborder Labyrinthodontia. Head of medium pro- 

 portions, with orbits near the middle of the length, and lateral external 

 nares. Epiotic bones prominent, bounding a deep auditory notch. Mandib- 

 ular angle projecting beyond the glenioid cavity. Maxillary and premax- 

 illary teeth not large, conic, subequal ; within them a series of rather 

 numerous teeth, of near the same size, probably rising from the palatine 

 bone. No lyra discoverable. 



This genus resembles BMnosaurus and Eryops, but belongs to the 

 group with prolonged mandibular angle. Among these it differs from 

 Mastodonsaurus and its immediate allies in the deep auditory notch and 

 prominent epiotic bones. From Labyrinthodon and Anthracosaurus, the 

 uniform sizes of its teeth distinguish it ; while there is no indication of 

 the facial fontanelle of Dasyceps, which is otherwise much like Parioxys. 



Char. Specif. This salamander is represented by two crania of similar 

 size, to one of which a few vertebra? are attached. I have not yet removed 

 the matrix enclosing the latter, as it is a task requiring much time. The 

 general form of the skull is a triangle with rounded sides and narrowed and 

 obtuse apex. The parietal region is rather elevated and wide, and is bounded 

 laterally by a low, angular ridge which extends anteriorly from the epiotic 

 angle, diminishing in prominence to the orbit. The external border of the 

 epiotic next the auditory notch is acute,, and the posterior angle is de- 

 curved, as though it formed the rim of a large membranum tympani. Be- 

 tween the epiotic cornua the supraoccipital border is concave The middle 

 of the parietal region is concave. 



The orbits are large and have prominent rims, which separate a concave 

 interorbital region, which is less than half as wide as the longest (antero- 

 posterior) diameter of the orbit. The rim is most prominent at the front of 

 the orbit, anterior to which the side of the muzzle is somewhat swollen. 

 There is no canthus rostralis ; in its stead there is a concavity behind the 

 nares, with an intervening swelling just behind the latter. These are 

 equally lateral and superior in their presentation. The middle of the 

 muzzle is slightly concave, with a low median longitudinal ridge. If there 

 be any sculpture of the surface of the cranial and mandibular bones, it must 

 be slight ; where the thin layer of fine grained matrix which invests it has 

 been removed, it is smooth. 



The crowns of the teeth are rather slender ; one from the posterior part 



PROC. AMEK. PHILOS. SOC. XVII. 101. 3m. 



