150 



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

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

 (reaches the tooth-line at the (ifth in H. coryphceus). 



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

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

 the superior and posterior directions. Tlie basisphenoid is strongly keeled 

 below. The qiiadratum is like that of H. coryphoius 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 vertehrcE displa}' the same disproportion in 

 size observed in H. ionjpliceus. 



Measurements. 



M. 



Length of the os quadrat um 0. C81 



Width of tho articular extremity of the os qnadriitum 0. 038 



Length of the dentary boue 0. s;80 



Length of the tooth of the dentary bone, third from behind 0.022 



Length of the tooth, crown only 0.016 



Length of the siispensorium from the foramen ovale 0. 108 



Total length of the cranium (23 inches) 0. ;3go 



This species cannot be confounded with the Liodou pruriger, Cope, and 

 L. congrops, Cope, owing to its depressed vertebral centra; from L. milchillii, 

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



PLA.TECARPUS CUKTIROSTRIS, Cope. 



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

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

 of the cranium, with several vertebrge, 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 abl)re- 

 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-hne. There are but 

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

 of P. coryplicnus. 



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- 



