6 BAUR. [Vol. VII. 



what compressed throughout, slightly sigmoid, and has both 

 ends moderately expanded. 



4. Qtiadrato-parietal Arch. — Professor Marsh states that " evi- 

 dence of the existence of this arch was first observed " by him 

 in the autumn of 1870, but, as we have seen, it was known 

 already to Goldfuss and Cope. 



5. Discovery of the Malar Arch. — This discovery was also 

 made by Goldfuss long ago ; Marsh only found the complete jugal. 

 It " is a stout bone, somewhat flattened, and bent at an obtuse 

 angle. It unites by suture with an external process of the post- 

 frontal. Its anterior extremity is united with the maxillary." 

 It has a pointed tubercle at the posterior external angle. This 

 description agrees with the complete jugals before me. 



6. Pterotic Bone. — This so-called pterotic bone is nothing but 

 an epiphysis of the paroccipital. It is present in Varanus and 

 other Lacertilia. The pterygoids, the correct nature of zvhich was 

 established already by Ciivier, are now described as palatines. 



Cope} 1875. 



In 1875 Professor Cope published his extensive work on the 

 Vertebrata of the Cretaceous formations of the West. The 

 order Pythonomorpha is retained. The following cranial char- 

 acters are given, which are said to distinguish the order : — 



1. The quadrate bone is attached to the cranium by a gingly- 

 moid articulation admitting of free movement. 



2. The opisthotic bone projects free from the cranium as the 

 suspensorium of the quadrate bone, and is supported and em- 

 braced by a pedestal projecting from the cranial walls, composed 

 of the pro-otic in front and the exoccipital behind. 



3. The stapes lies in a groove on the posterior side of this 

 suspensorium, and is produced to the os quadratum. 



4. There is no quadratojugal arch. 



5. The parietal bone is decurved posteriorly, forming the 

 cranial wall in front of the pro-otic. 



6. The brain chamber is not ossified in front. 



7. The squamosal bone is present, merely forming the poste- 

 rior part of the zygomatic arch. 



^ Cope, E. D., The Vertebrata of the Cretaceous Formations of the West, U. St. 

 Geol. Surv. Terr., Vol. II, Washington, 1875. 



