380 University of Kansas Geological Survey. 



zontal extent, being a high, narrow opening, and differing 

 materially from what they are in T. latiremis, where the opening 

 is broader than high. 



The frontal is elongate antero-posteriorly, joined with that of 

 the opposite side. Anteriorly the two become narrowed and 

 pass between the divergent ends of the prefrontals. The middle 

 portion of the outer border is concave, and forms the upper part 

 of the orbital rim. The posterior end is the broadest part of the 

 bone, and presents a semicircular articular margin for the 

 parietals and postorbito-frontals. On the inferior surface of 

 each bone there is a sharp ridge, running antero-posteriorly. 

 These ridges inclose between them a deep groove, which be- 

 comes wider at the posterior end. 



The parietals are wanting in the material at my command. 

 Cope says in describing the type specimen : " The free border 

 of the parietal on one side, though not well preserved, indicates 

 that the temporal fossa is partly roofed, as in Chelydra.' ' 



The postorbito-frontals are not preserved. 



The orbit was large, oval in outline, with the greatest diam- 

 eter antero-posterior. The superior and inferior borders are 

 " subparallel for a short distance." 



The squamosal and petrosal are indicated by fragments at- 

 tached to one of the pterygoids, but are too imperfect for de- 

 scription. 



The supraoccipitql is represented by the posterior median proc- 

 ess ; this is very large, with considerable vertical, as well as 

 antero-posterior extent. The lower edge is straight, and the 

 upper strongly convex, forming nearly a semicircle. 



The pterygoids- are closely united in the median line, and 

 extend forward to join the palatines. They are slightly con- 

 tracted before the lateral process is given off to join the 

 quadrate. Posteriorly the pterygoids are separated by the 

 basisphenoid, which is wedged in between them, and appears 

 on the lower surface a rugose, triangular, somewhat concave 

 surface. 



The quadrate is short and strong. The sides of the stapedial 

 notch are so closely approximated that it may be best described 



