36 AMPHIBIA AND PISCES OF THE PERMIAN OF NORTH AMERICA 



after diverging strongly from the symphysis, are strongly incurved to the 

 quadrate, a form not found in E. megacephalus. The sculpture is more 

 sharply defined in the present species. In the vertebra;, although the inter- 

 centra have the same degree of ossification as in the E. megacephalus, the 

 neural spines have not the expanded head of those of the larger species, 

 but look as though they had lost an epiphysis, as in the case of the humeri. 

 They are erect, with subquadrate section, and not oblique and grooved as 

 Trimerorhachis insignis. The diapophyses are more elongate than in E. 

 megacephalus, and their extremities frequently have a subround or suboval 

 section, and but few have the narrow surface seen in E. megacephalus. The 

 ribs are short and fiat, and have the distal extremities expanded paddle- 

 shape. Laid backwards such a rib reaches to the posterior edge of the third 

 diapophysis posterior to the one to which it is attached. 



"The form of the skull is triangular, with rounded apex or muzzle, and 

 a slight contraction behind the nostrils. The latter are near the edge of the 

 jaw and open equally laterally and superiorly. The orbits are of medium 

 size and are as far from the edge of the jaw as the width of the interorbiul 

 space, which is about as wide as the diameter of an orbit. The posterior 

 'table' is flat with decurved lateral edges, which rest in a squamosal suture 

 on the squamosal or quadratojugal and quadrate bones. Its posterior angle 

 is produced downwards and backwards to near the distal extremity of the 

 quadrate. The latter slopes posteriorly and downwards. The quadrato- 

 jugal region is strongly convex in vertical section. The mandibular ranius 

 is strongly incurved posteriorly, from a point opposite the free extremity 

 of the pterygoid. The symphysis mandibuli is short. 



"The sculpture is distinct on all the superior surfaces of the skull, and 

 consists of fossse of medium size, bounded by irregular, narrow ridges. There 

 are three fossae in 10 mm. The fossae are obsolete on the extremity of the 

 muzzle and on the anterior part of both jaws. 



"The teeth are a little longer on the premaxillary than on the maxillary 

 bone. There are five on each, or six, if the tooth below the nostril belongs 

 to the premaxillary bone. The palatine teeth are much larger. The_ first, 

 perhaps standing on the external edge of the vomer, is a little posterior to 

 the line of the external nostril. The second is half-way between the nostril 

 and orbit, and the third is alongside of and just posterior to it. The fourth 

 is opposite a point a little posterior to the middle of the orbit. Their sur- 

 face is as yet obscured by a thin layer of fine indurated mud, which in some 

 instances can not be removed without destruction of the tooth surface. _ 



"The intercentra of the vertebrae are, as in Eryops megacephalus, ossified 

 so as to nearly cut off the chorda dorsalis, but unlike that species they are 

 not notched on one side of their lateral apices. The extremities of the neu- 

 ral spines are subquadrate, rounded behind, and flattened anteriorly. The 

 edges of the postzygapophyses are prominent and flared upwards. 



"The scapula is robust and flat, having the posterior-external border 

 longest and concave, and the superior-posterior convex. In my specimens 

 the thin anterior edge is broken. The coracoid appears to be coossified with 

 the proximal external edge of the scapula and is directed downwardsand 

 backwards. Its extension is small, and terminates in an apex posteriorly 

 and a thick double edge inferiorly. The glenoid cavity borders this edge 

 and is small. The epicoracoid, if it existed, is lost. The thick, inferior edge 

 of the coracoid and scapula is similar to those of the humerus and vertebral 



