WILLISTOX: NEW CRETACEOUS TURTLE. 7 



near the middle of the orbital margin, there was evidently a thin 

 expansion downward, but the edge has been broken off, so that one 

 cannot say to what extent. Its ascending process to join the pre- 

 frontals is about one inch in width between the nares and orbits. The 

 Xares. external nasal opening is cordate in shape, with a rounded 

 anterior angle. The plane of its margins looks upwards and forwards 

 at an angle of about thirty-five degrees from the perpendicular. The 

 Ori)it8. posterior margin of the orbits is almost exactly in the mid- 

 dle of the a-nterio-posterior diameter of the skull. Their shape is 

 irregularly oval, the greater diameter being from before back. Their 

 superior margin, as far back as the fronto-postfrontal suture, is paral- 

 lel with the median line of the skull; it then turns obliquely outward, 

 with a gentle convex border, to the middle of the hind margin. The 

 plane of their margins is not more than ten or twelve degrees from 

 the vertical, and is turned outward and forward at an angle of about 

 thirty-five 'degrees. The margins are everywhere thin. The man- 

 Mandible, dibles have been firmly compressed upon the maxil- 

 laries, and are posteriorly somewhat flattened. They are stout and 

 heavy, with a thin inferior margin throughout most of their extent. 

 The genial margin is gently convex and considerably receding. The 

 superior margin was evidently thin, like that opposing it. Their 

 articulating surfaces cannot be clearly made out, as the quadrates 

 have been crowded upon them. They appear, however, to be lightly 

 convex. The two sides show no trace of a suture between them. 

 Palatines. The palate is remarkable for its extreme concavity, and 

 the anterior position of its choante. All posterior to the pterygoids 

 has been so crushed that it is impossible to determine the characters. 

 Pterygoids. The pterygoids are short and narrow, concave on the 

 sides, extending out in front to form a rounded, vertical, ectoptery- 

 goid process, just in front of which is the distinct, transverse, pala- 

 tine suture. The palatines continue the full width of the pterygoids 

 in front, and are gently concave, with a rounded margin on the sidts 

 as far as the process. These processes curve outward and forward 

 nearly horizontally to unite with the maxillaries, which do not send a 

 distinct process out to meet them. Near the posterior border of the 

 process, well out towards the extremity, there is a small palatine for- 

 amen, leading up into the floor of the orbit at about its middle, and 

 vertically below, or a little to the inner side of the innermost part of 

 the superior margin of the orbit. On the left side there appear to be 

 two foramina. Almost from the posterior margin of the palatines the 

 surface begins to ascend obliquely forward, forming a deep channel, 

 which in the anterior half is divided into two by a strong median 

 ridge. Unfortunately the suture with the vomer cannot be made out. 



