BAENIDJE. 89 



Nasals are present. The frontals are triangular, with one apex directed to the corre- 

 sponding orbit, without reaching it. The exoccipitals meet in the midline neither above nor 

 below the occipital foramen. The occipital condyle belongs wholly to the basioccipital. On 

 the lower side of the skull the pterygoids exclude the quadrates from contact with the basioc- 

 cipital and the basisphenoid. The latter bone does not quite reach the vomer. On each side 



of the basioccipital is a foramen, doubtless for a vein, wrongly regarded formerly by the 

 author as for the internal carotid artery. 



The choanae are placed far forward. There is no masticatory ridge on the maxilla. Just 

 within the rim of the orbit there is a distinct suture which cuts off the lacrimal from the 

 prefrontal. 



The lower jaw (fig. 81) presents a rather broad grinding surface. 



The femora of this specimen are present. The total length is 107 mm. The head is 

 comprest. The plane passing through this head would come into contact with the tibial 



FIGS. 78 AND 79. Chisternon hebraicum. Skull. Xj. No. 5961 A. M. N. H. 



78. Seen from above, fr, frontal; mx, maxilla; na, nasal; pa, parietal; pro, prootic; sq, squamosal. 



79. Seen from below, ju, jugal ; mx, maxilla ; pal, palatine; pt, pterygoid; qu, quadrate; qu. art, articulation 



of lower jaw; sq, squamosal; vom, vomer. 



border of the distal end of the bone. In Trachemys elegans this plane makes an angle of 

 perhaps 40 with the axis of the bone on the tibial side. The diameter of the shaft of the femur 

 of the species here described is 1 1 mm. The width of the distal end is 31 mm. 



No. 5904 of the American Museum was also found at Grizzly Buttes. It is believed to 

 belong to the present species. It furnishes a large shell nearly complete, a portion of the skull 

 and lower jaw, the neck, the shoulder-girdle, and the complete pelvis. The carapace has an 

 axial length of 505 mm., and a maximum width of 470 mm. The carapace is moderately convex 



