207 



Portheua. The margin rises steeply to the dentary, whieli presents a nar- 

 rowed rectangle behind. The alveolar margin has two convexities, witli a 

 depression between; the syniphyseal angle is not prominenl. The lower 

 posterior angle of the dentary is quite prominent for muscular insertion. Tlie 

 crowns of the teeth are cylindric, slightly curved inward. The dentary bones 

 of the second specimen coincide with these in all respects. 



Thirty-three vertebra are preserved, all deeply two-groovcid on the sides. 

 The ribs are articulated by a sigmoid surface to a l)road, short element of a 

 sigmoid form, which is inserted in the lateral groove of the inferior face, or 

 articulated by gomphosis. 



The ventral spines already noticed are quite flat, witliout serrate edge, 

 but with some rugosities near the edge on one side only. There are no grooves 

 on the upper side, but the dense bone is delicately striate. 



Measurements. 



M. 



Length of the prcnuixillnry 0. 033 



Depth of the premaxillary 0.045 



Depth of the maxillary at the condyle 0.037 



Tliickness of the maxiUaiy just behind the condyle 0.012 



Length of the mandibular ramus 0. 172 



Length of the angular process 0. 014 



Depth at the corouoid process 0. 0.")8 



Depth at the symphysis 0. 04 1 



Length of eight vertebnu 0.212 



Width of the articular face 0. 0;;0 



Width of rib 0.004 



Width of the ventral spine .at the middle 0. 025 



Length of the ventral spine (fragment) 0. l.'io 



Length of the condyle of t he inferior quadrate 0. 020 



The scales associated with this species were tJiiii and cycloid, and diffi- 

 cult to preserve. 



From near t!ie Smoky Hill Uiver, Kansas. 



IciITHYODECTES CTENODON, Cope. 



Proceedings of the Ainri icaii P]iili)sopliical Society, 1870, November ; H.ayden's Geological Survey of Wy- 

 oming, &c., 1871, p. 421, part. 



Found l)r Profiessor Mudge on the North Fork of the Smoky Hill River; 

 common in many other localities. 



This species is established on one complete maxillary bone, and three- 

 fourths of the other, a large part of the dentary bone, witli tlu! entire dental 

 series, and numerous portions of cranial bones. These, according to Profes- 

 sor Mudge, were found together, and, to all appearance, belong to the same 

 aniiuiil. 



