118 The Ottawa Naturalist [January 



in an excellent state of preservation and is but slightly distorted. The 

 sutures are very distinctly marked defining the exact limits of the 

 various elements. The smaller skull is imperfect in the occipital 

 region but elsewhere most of the sutures are clearly displayed ; it is of 

 special value for comparison with the larger specimen. 



The larger skull is selected as the type of the new genus for which 

 the name Cheneosaurus (Gr. Cheneios) is proposed on account of the 

 supposed resemblance of the specimen, when viewed in profile, to the 

 outline of the head of a goose. The species is named after Tolman 

 ferry and post-office, both of which are not far from where the type 

 was discovered. 



. Cheneosaurus tolmanensis gen. et sp. now 



Generic and specific characters. Skull small, high, short, dome- 

 shaped above, and steeply descending in front. Domed prominence 

 formed by frontals, nasals, prefrontals and supraorbitals. Lachrymal 

 small. Nasals broad, covering the narial passages. Narial opening 

 small and placed very far forward. Anterior premaxillary portion 

 broadly expanded and terminating almost squarely in front. Mandible 

 strongly decurved anteriorly. Teeth long and narrow, with marginal 

 papillation at the apex to a varying extent. Orbit broadly ovate. 

 Lateral temporal fossae long and narrow. Supratemporal fossae small. 



This genus of the Edmonton formation differs from all other 

 known members of the Trachodontidae in the dome-shaped form of 

 the upper, interorbital surface of the skull, and in the roofing over of 

 the narial passages by the broad nasals, resulting in a diminution of the 

 anterior nares and their limitation to a far advanced position. In no 

 other form is the angle of descent of the facial portion so uniformly 

 steep. Attention is called to the presence in Cheneosaurus of a large 

 supraorbital, a cranial element not hitherto recognized in the 

 Trachodontidae except doubtfully in the single instance of Gryposaurus 

 (Belly River formation). 



The skull of Cheneosaurus tolmanensis is broad behind and 

 narrow in front. It is most elevated in the region above the orbits and 

 for a short distance forward, forming a conspicuous rotundity in the 

 upper surface in advance of which it descends narrowly and steeply to 

 the horizontally expanded snout. Behind the apical prominence the 

 remainder of the superior surface is depressed. The mandible is long 

 in comparison with its height and is strongly decurved in front where 

 it ends in a broad predentary. The height of the type skull is less 

 than three-fourths its' length, and its maximum breadth is nearly one- 

 half its length. The orbit is moderately large and is situated toward 

 the front of the posterior half of the cranium. 



By referring to the two drawings of the type, reproduced herewith, 

 one a right side view, the other from above, the proportions of the 



