1895.] 455 [Cope. 



Measurements. mm. 



Length from orbit to end of muzzle (axial) 47 



Interorbital width 25 



Internareal width 29 



Diameter of orbit 13 



Width of mandible at quadrate So 



Length of four vertebrse over arches 30 



From the Permian of Texas. 



DiPLOCAULusMAGNicoKNisCope, Proceeds. Amer. Philos. Soe., 1882, p.453. 



This is an abundant species in the Permian beds in Texas. I take ad- 

 vantage of a specimen in which the skull is better preserved than in the 

 type, to describe its segmentation, and also the disposition of the teeth. 



In the typical specimen the posterior border of the skull was not pre- 

 served. Tlie present specimen shows that it is continuous from the 

 extremity of one horn to that of tiie other, and regularly concave without 

 angles, and that it overhangs the occipital condyles a little. The posterior 

 parts of the horns consist of the tabular bones, and the anterior portion 

 consists of the supratemporals. The inferior part of the base of the horn 

 externally consists of the element which articulates with the quadrate, 

 or qurtdratojugal. It is distinguished from the supratemporal by a hori- 

 zontal suture. A considerable part of its surface presents inferiorly. The 

 supramastoid lies between the supratemporal and the postfrontoorbital. 



The supraoccipilals extend well forwards on the superior face of the 

 cranium, the median suture equaling the length of the parietal bone. 

 They have an extraordinary transverse extent. The median suture of 

 the parietals is rather longer, and it is separated by the small parietal 

 foramen at a point one-third its length from the frontal suture. The 

 posterior width of the frontal is equal to three-fifths its length, and is a 

 little greater than the intfrorbital width. It extends as far anterior as 

 posterior to the orbits. The posterior suture is trilobate. The postfron- 

 tals are suboval with the long diameter at 45° to the median line, and the 

 anterointerual border excavated by the orbit. They do not advance ou 

 the internal border of the latter, resembling the prefrontals in this re- 

 spect. The supramastoids are necessarily well produced forwards to meet 

 the short postfrontals, advancing far anterior to the posterior border of 

 the jugals. 



The premaxillaries are short and wide, and are widely truncate by 

 the frontal posteriorly. The prefrontals do not extend posteriorly to 

 the inner border of the orbit, but they join the jugal by a considerable 

 suture. The nasals occupy their usual position, and are rather small ; 

 one of them is fused with the premaxillary in the specimen. The max- 

 illaries are small, especially the facial part, which does not reach the 

 orbit. The jugal is a relatively large bone, and has an irregular poste- 

 rior outline, where it joins the quadratojugal and the supratemporal. 



The great expansion of the roof-bones posterior to the quadrates, is 

 associated with a considerable expansion of the pterygoids in the same 



PaOC. AMER. PHILOS. SOC. XXXIV. 149. 3 F. PHINTED FEB. 18, 1896. 



