1883.] 633 [Cope. 



yond the exoccipital bone. In a specimen of Empedias molaris* there is a 

 meatus auditorius, in which the stapes was not found on cleaning: out. 

 This element is coosified with the surrounding bones laterally and poste- 

 riorly. Consequently when broken open, the vestibule is represented by 

 two deep grooves, directed inwards and anteriorly. 



The single species of this genus is one of the largest saurians yet obtained 

 from the Permian of Xorth America. 



Char, specif. The superior surface of the skull is everywhere flat, as is 

 the external face of the maxillary. The surface of the latter is marked by 

 moderately coarse fossae and grooves, separated by more or less fine irregu- 

 lar but generally longitudinal ridges. The minute sculpture of the supe- 

 rior cranial surface, is finer and more punctate in character. The arege of 

 this surface, already mentioned, are arranged as follows : There is a series 

 over the orbits, which are separated from each other by straight grooves, 

 and which grow larger and more swollen posteriorly. Between these su.- 

 praorbital rows, the are* of the top of the skull are separated by longitu- 

 dinal grooves, except immediately between the widths of the orbits, where 

 there are some narrow transverse arese. On the supraoccipital region there 

 is a median subtriangular area, and three narrow longitudinal ones on 

 each side of it. External to these, and on the posterior part of the squa- 

 mosal region, the arese are larger and more swollen. A cluster of three of 

 these lies between the exoccipital bone, and the smooth descending surface 

 of the posterior edge of the squamosal. Of these the one bounding the ex- 

 occipital bone, is a robust cone, forming a short horn, like that occupying 

 a similar place in the horned toad, Phrynosoma douglassi. Between the 

 temporal arese, and in front of the supraoccipital arese, on each side of the 

 middle line, there are three longitudinal arese, which are successively nar- 

 rower externally, the exterior being very narrow. On the frontal region 

 anterior to the transverse arese, are two wide longitudinal arese. Each 

 nasal bone has a small median area, from which radiate grooves, of which 

 some of the posterior are close together. 



The occiput is excavated into a large fossa on each side of a large trian- 

 gular supraoccipital region. The fossse are bounded externally by a strong 

 exoccipital crest and at the anteroinferior corner by the "opisthotic." 

 This bone projects posteriorly and downwards, in the form of a robust 

 hook. The foramen magnum is not excavated so abruptly above the ex- 

 occipital facets as in Empedias molaris. 



Measurements of Skull and Femur. M. 



Interorbital width 108 



Length from supraoccipital crest to frontonasal suture. . .135 

 Width between apices of tuberosities of the inter calaria. .113 

 Length from apex of tuberosities to inferior extremity of 

 quadrate 129 



* Figured in the Proceed. Amer. Philos. Soc. xix. p. 56. 



