Case.] Turtles. 379. 



Toxoclielys serrifer. 



To.vochelys serrifer Cope, Cret. Vert., p. 299. 



The skull of this species is represented in the University col- 

 lection by the anterior portion, the quadrates, the basisphenoid, 

 the pterygoids, the supraoccipital and petrosal, and the anterior 

 part of the mandible. 



The maxillaries have a flat, broad, alveolar space posteriorly, 

 the cutting edge evidently rising sharply, though quite low. 

 Anteriorly the edge becomes deeper, and the face of the alveolar 

 space is quite concave. Posteriorly there is a broad suture for 

 the jugal, and anteriorly the maxillaries unite with the pala- 

 tines and premaxillary. The union with the palatine is marked 

 by a prominent rugose ridge, much stronger than in T. latiremis. 



The premaxiUaries are short, deeply concave on their lower 

 surface, with a deep cutting border. Posteriorly they unite 

 with the palatine and vomers, laterally with the maxillaries, 

 externally they form the lower margin of the external nares. 



The palatines are incomplete posteriorly. Anteriorly they are 

 thickened and rugose, forming the prominent margins men- 

 tioned. They are united with the vomer on the median line. 

 The anterior border of the vomer is excavated by a deep groove, 

 from the posterior extremity of which a ridge extends posteriorly 

 along the median line separating the choanse. These are oval 

 in outline, and extend almost directly forward. There were 

 probably palatine foramina at the posterior end of the palatines, 

 but they are not indicated in the specimen. 



The prefrontals are elongate antero-posteriorly, and join in 

 the middle line in front, where they form the upper border of 

 the external nares. Posteriorly they diverge, leaving a V-shaped 

 area, which clasps the anterior part of the frontal. The pre- 

 frontals extend backward to near the middle of the upper border 

 of the orbit. They are joined to the vomer below by descend- 

 ing processes from their anterior part. 



The external nares are formed by the premaxiUaries below, the 

 ascending processes of the maxillaries laterally, and the pre- 

 frontals above. They have a much greater vertical than hori- 



