208 



rpi 



he ilriiuil characters differ from those of Saurocepfialus, as aljove 

 pointed out, and resemble more those of Saurodon leantts. The crowns of the 

 teeth are more exserted and slender. The inner face of the crown is more 

 convex than the outer; but there is no angle separating the two aspects. 

 The apex is moderately acute, and directed a little inward, owing to a slight 

 convexity of the external face. Enamel smooth. The alveoli are very close 

 together, and are probably only separated in their deeper portions. There 

 are forty-two teeth and alveoli in the maxillary bone. The superior condyle 

 is low, and its anterior border falls opposite to the last tooth, or the indented 

 surface wliich wns occupied by the premaxillary bone. The more proximal 

 part of the maxillary curves inward and backward behind the position of the 

 premaxillary, more than in S. inognathus. Tne maxillary is a rather thin and 

 narrow bone, with a broad obtuse and thinned extremity. Its superior mar- 

 gin is marked with one or more acute ridges, which look as though it had a 

 contact with a large preorbital bone. The alveolar border is nearly straight. 

 The dentary bone is remai'kable for its straightness and laminar charac- 

 ter, and for the depth of the symphysis. The length of the latter is preserved, 

 wliile posteriorly to it the lower margin of the dentary is broken away. The 

 alveolar margin is slightly concave, and unites with the symphyseal at an angle 

 of 65°. There are twenty-six teeth and alveolae, which grow a little larger 

 to the posterior extremity of the series ; anteriorly, the alveoli are confluent 

 externally, but, posteriorly, the septa are frequently complete, though thin. 

 In neither this bone nor the maxillary are to be found the foramina along the 

 bases of the teeth, characteristic of Saurocephalus or Saurodon, as pointed 

 out by Harlan and Hays. 



Measurements. 



M. 



Ltfngtb of the maxillary bone 0. 158 



Depth at the condyle .' 0.031 



Depth at the extremity 0.022 



Length of the crown of a tooth , 0. OOGl 



Diameter of the crown at the base 0. 00:>S 



Length of the alveolar border of the dentary 0. 106 



Depth of the symphyseal border of the dentary 0.047 



Length of the oper^nlar condyle 0. OlS 



Several osseous ventral rays accompany the cranial bones ; they are prob- 

 ably interior in position, and are much more slender tlian the ventral spines 

 observed in /. annides and /. prognathus. Tliey are subquadrate in section, 

 not sculptured nor enameled; there is a shallow groove on the side. 



