a KANSAS UNIVERSITY QUARTERLY. 



The posterior narial openings are extraordinarily large, and situated 

 far forward, almost immediately below the anterior openings. Each 

 opening is large, and its plane looks upwards, forwards and inwards. 



General characters of the skull. 



The skull is elongate, narrow and high. It tapers on the sides from 

 near the quadrates to the front margin of the orbits, whence the 

 muzzle forms an acute, somewhat convex cone. The superior surface 

 from the front margin of the nasals is only lightly arched, but with a 

 rounded boss back of the middle. The surface is nearly smooth, or 

 with delicate striae, except near the front end, where it has numerous 

 small, rounded pits. The orbital and nasal margins are sharp. 



The principal dimensions of the specimen are as follows: 



P^xtreme length 205 mm. 



Width through cjuadrates 145 



Height 95 



Length of mandibles 155 



Width between orbits above 58 



Greatest width between the orbits posteriorly 105 



Antero-posterior diameter of orbits 60 



Width of orbits 42 



Transverse diameter of nares 31 



Antero-posterior diameter of same 31 



Least width of pterygoids 22 



Width through the ectopterygoid processes 46 



Least width of the palatines • 43 



Antero-posterior diameter of posterior nares 24 



Transverse diameter of same 18 



Distance between choanae 16 



Width between palatine foramina 48 



Width of mandible through symphysis 43 



Width of mandible below orbit 24 



The skull, as will be seen from the description and the figures, has 

 a great resemblance to that of the sea-turtles, the rostrum being 

 somewhat less narrow than in Chelonc, but from which it differs 

 conspicuously in the presence of free nasals, the presence of palatine 

 foramina, the structure of the palate and the anterior position of the 

 choanas, and the convexity of the maxillary condyle. Its resemblance 

 to RJiinoclielys, from the Cambridge Greensand seems greater, so 

 far as I can judge by the figures given by Lydekker. Like that, it 

 has free nasals, the pterygoids narrow and emarginate, the palatines 

 ]irobably meeting in the middle line, the prefrontals separated, the 

 jugal continuing the line of the alveolar border to the quadrate, man- 

 dible with the interdentary suture obliterated, and with a prominent 

 oral margin. From it there seem to be ample generic differences. 

 There are no indications of epidermal shields in the present skull. 



