Cyclopidius (Pithecistes) Cope, etc. 411 



their posterior termination being but slightly back of the 

 line of the anterior orbital margins; the forehead is 

 slightly elevated along the sagittal plane and more 

 prominently at the supra-orbital borders; the infra- 

 orbital foramen is above the posterior edge of P^ ; the 

 face in advance of the orbits is quite narrow ; the bullae 

 are very much inflated; the palate is nearly flat; the 

 glenoid articular surface is much more convex downward 

 than in Oreodon; there is a marked fossa at the anterior 

 base of the postgienoid tubercle; this latter process is 

 small and is composed apparently half of the squamosal 

 and half of the tympanic bone, the dividing line in No. 

 10122 being a transverse vertical plane ; the superior 

 skull contour is a nearly straight gentle slope from the 

 summit of the inion to the tip of the nasals; the bullae 

 are so greatly inflated that they are separated by an 

 interval only 2 mm. in diameter; the frontals are 

 produced between the nasal bones, which end in a wedge 

 in the frontals. 



The superior molars differ from those of the other 

 species in that the size reduction from M-^ to M^ is much 

 greater, the antero-posterior diameter of IVP being less 

 than one half that of M^. The hypocone of M^ is quite 

 small, while the metastyle is relatively large and promi- 

 nent. The metacone is rotated inward more strongly 

 than in L. decora or L. major. The premolars have a 

 decided backward slope from root to crown, which does 

 not occur in the Yale specimens of either of the other 

 species. 



Although No. 10122 is a robust specimen, I am inclined 

 to believe that Leidy did not accurately estimate the 

 length of the superior molars. He stated it to be 20 mm., 

 and yet the length of M^ plus M^ in the type specimen is 

 13 mm. M^ is lacking in the t^^pe. In all of the Yale 

 specimens, the antero-posterior diameter of LP is more 

 than 10 mm. 



Measurements. 



(Cat. No. 10122, Y. P. M.) 



mm. 



Skull, len^h from oceip. condyles to canines, inc 95 



Bizj^gomatic diam 65 



Diam. of postorbital constriction 21 



Max. width of brain-case 36 



