CYCLOPIDIUS 



257 



portion of the zygoma is relatively deep, although not very thick, except near and at its point of 

 origin, centrally located above M 2 . The anterior part turns outward abruptly above M 1 and does 

 not gradually blend into the muzzle, as it does in Cyclopidius proper. The malar extends back to 



fO/23, TYPE 

 Y. P M 



[84. — Cyclopidius (Chelonocefhalus) schucherti Thorpe. Superior view of skull. 



Nat. size. (After Thorpe, 1921.) 



HT. Cat. No. 10123 Y.P.M. 



the glenoid surface. The squamosal part of the zygoma is very weak, has a thin edge superiorly, 

 and rises in the line of the malar to its highest point above the glenoid surface. The facial vacuities 

 are very large and extend back to a line almost through the anterior part of the postorbital processes. 



SO/23, TYPE 

 Y P M. 



Fig. 185. — Cyclopidius (Chelonocephdus) schucherti Thorpe. Left half, inferior view of skull. HT. Cat. No. 10123 



Y.P.M. Nat. size. (After Thorpe, 1921.) 



Anteroinferiorly they extend to within 1 3 mm. of the alveolar parapet of the premolars. The nasals 

 are missing but undoubtedly joined the maxillaries in the anteriorly expanded Cyclopidius manner. 

 The lacrimal bone is very small and bears a small, shallow depression. The frontals are excessively 

 shortened anteroposteriorly, and are gently hollowed transversely between the mid-line and the 

 upper orbital borders. The orbits are very small and presumably closed posteriorly, although com- 

 plete bars are missing, but the postorbital processes on the malar and frontal indicate a complete 

 closure. The orbits are well elevated and look almost wholly upward, but somewhat outward. 



