AVilliston.] Turtles. 357 



extraordinarily large, and situated far forward, almost immedi- 

 ately 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 : 



Extreme length 205 mm. 



Width through quadrates 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 choana? 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 Chelone, but from which it 

 differs conspicuously in the presence of free nasals, the presence 

 of palatine foramina, the structure of the palate and the ante- 

 rior position of the choanae, and the convexity of the maxillary 

 condyle. Its resemblance to Rhinochelys, from the Cambridge 

 Greensand, seems greater, so far as I can judge by the figures 



