Cope.] 524 t , Jarl . i8, 



The side is divided by the gentle convexity continued forwards from the 

 malar region. Below this and above the premolars the face is concave. 

 Above it the preorbital fossa is well marked, though not deep, and gradu- 

 ally fades out anteriorly. The interorbital region is flat, as in M. macroste^ 

 gu8, and the supraorbital border is not decurved, as it is in M. superbus and 

 M. montanus. The supraorbital and preorbital borders of the front are, 

 however, not continuous as in M. rnacrostegus, though nearly in the 

 same line, which they are not in M. superbus. The orbits are more oblique 

 than in M. superbus, looking more upwards and forwards, and their verti- 

 cal exceeds their transverse diameter. The malar bone though oblique, is 

 more vertical than the orbit below the latter, and has an uninterrupted 

 gently concave surface. The postorbital bridge is narrow, and consists 

 one-half of the malar and one-half of the frontal bones. The inferior edge 

 of the malar is thin and is slightly convex downwards, and passes behind 

 the protuberant squamosal at a point behind the line of the postfrontal pro- 

 cess. The anterior extremity of the squamosal is not protuberant below the 

 orbit and only begins to rise gradually below the line of the postfrontal 

 process. It then expands rapidly downwards and outwards in a strong 

 curve, with its flat surface looking upwards as much as outwards. After 

 making a short downward turn it rises steeply, contracting gradually in- 

 wards, and presenting a convexity posteriorly, with its truncate edge 

 looking outwards. Its apex is nearly on a level with the sagittal crest. 

 The inner or descending edge of this process. is concave, so that the apex 

 overhangs a little the posterior outlet of the temporal fossa. The anterior 

 temporal angles are strongly marked and unite into a sagittal crest. The 

 edge of the crest is thickened, so that its section is a letter T. 



The supraoccipital bone presents a wide flat convexity above the foramen 

 magnum, in distinction from the stronger convexity of M. superbus, and 

 the still stronger of the M. rnacrostegus and M. montanus. As in the other 

 species, the posttemporal (= lateral occipital) crests are only present 

 at the upper half of the occiput. Between them there are two ligamen- 

 tous or tendinous insertions, but no median keel. The exoccipital and 

 posttympanic borders form a tuberosity below the meatus auditorius, which 

 passes upwards into a short convex posttemporal crest. The paroccipital 

 process nearly reaches the postglenoid by its anterior external edge. The 

 tympanic is complete, is not keeled below, and extends itself as a lamina 

 over the posterior side of the postglenoid process. The section of the 

 basioccipital is open V-shaped. The inferior flat surface of the sphenoid 

 is produced backwards in a wedge-shaped prominence to a line connect- 

 ing the anterior edges of the paroccipital processes. It has the same form 

 in M. macrostegus, but in three skulls of M. superbus, where it is visible, 

 the apex of the wedge does not extend posterior to the middle of the otic 

 bullae. The bullae are small and subcorneal, and reach as far as the ante- 

 rior edge of the postglenoid process. In the latter the transverse diam- 

 eter exceeds the anteroposterior, which exceeds the vertical diameter. 

 This process and the otic bulla are of about equal protuberance. In four 



