150 



The plate is more expanded than in the last-named species, especially 

 the thickened inner margin, which only approaches the basis of the last tooth 

 (reaches the tooth-line at the fifth in H. coryphaius). 



The occipital crest is low, and directed obliquely forward from the foramen 



magnum. The suspensoria are stout, and directed at an angle of 45° in both 



the superior and posterior directions. The basisplienoid is strongly keeled 



below. The quadratum is like that of H. coryphaeus in its massive external 



angle and ridge, but differs in the shorter hook and the non-interruption 



of the groove between the internal angular ridge and the knob below the 



meatus. The cervical and dorsal vertebra display the same disproportion in 



size observed in H. curyphceus. 



Measurements. 



M. 



Length of the os quadratuui 0. 081 



Width of the articular extremity of the os quadratum 0. 038 



LeDgth of the dentary bone 0.280 



Length of the tooth of the dentary bone, third from behind 0. 022 



Length of the tooth, crown only 0. 016 



Length of the suspensorium from the foramen ovale 0. 108 



Total length of the cranium (23 inches) 0.580 



This species cannot be confounded with the Liodon proriger, Cope, and 

 L. congrops, Cope, owing to its depressed vertebral centra ; from L. mitc/allii, 

 DeKay, the equal and numerous pterygoid teeth separate it at once. 



Platecaepus cuetieostbis, Cope. 



The. specimen below described was found by the writer on the denuded 

 foot of a bluff on the lower part of Fossil Spring Canon. The posterior part 

 of the cranium, with several vertebra?, was found exposed, and many other 

 bones, including the cranial, were found only covered by the superficial 

 washed material. Other portions were exposed on excavating the blue-gray 

 bed of the side of the spur adjoining. The name has reference to the abbre- 

 viation of the head and jaws. These are relatively shorter than in any other 

 species here described where these parts are known. The end of the muzzle 

 does not overhang, but descends gradually to the tooth-line. There are but 

 ten maxillary teeth and two premaxillaries on each side. Size about that 

 of P. coryphctus. 



■ Characters. — Cervical and dorsal vertebrae with transversely oval articular 

 faces, which are little depressed, and, though not continued to the base of the 

 neural arch, are scarcely excavated above for the neural canal. The diapophy- 



