FOSSIL REPTILES. 261 



bones, formed like trumpets^ widen on each side of the cra- 

 nium. The temple is a wide horizontal foss, but not deep. It 

 is uncovered, except on the back part, by the union of the 

 posterior angle of the parietal with the masto'idean bone. The 

 osseous temporal is reduced to a mere vestige. 



The two maxillaries form a transverse arch, at the middle of 

 which, underneath, is a single interparietal bone, and above the 

 external aperture of the nostrils, which in the fresh subject is 

 continued in a small fleshy trunk. The two palatines, and 

 between them the vomer, fill the concavity of this arch under- 

 neath, and have in front of them the two hinder nostrils consi- 

 derably separated, but the palatines do not surround them 

 below. At the posterior edge of the palatine is a tolerably large 

 pterygo-palatine. 



The anterior and posterior frontals form the upper part of 

 the orbits. The principal frontals advance between the ante- 

 rior as far as the edge of the external nostrils. There are no 

 nasal bones, no more than in the other tortoises. 



The jugal bone takes its place from the posterior angle of 

 the orbit, between the maxillary and the posterior frontal, 

 which it does not pass, touching a little on the pterygoi'dean 

 behind and underneath, but forming no projection behind to 

 border the temple. The temple is thus separated from the 

 orbit by a postorbital branch of excessive breadth, which takes 

 up the totality of the posterior frontal and jugal bones. 'J'he 

 posterior frontal is itself articulated to the pterygoi'dean bone by 

 its external hinder angle. The rest of its hinder edge is free, 

 and continues with that of the parietal to cover a wide and flat 

 canal of communication, going from the temple to the orbit, 

 and formed underneath by the pterygoidean and palatine bones. 



The two pterygoidean bones are enormous. They form the 

 greatest portion of the basis of the cranium and the ground of 

 the temple. Their external edge is curved in its anterior part 

 to continue with the free edge of the posterior frontal. There 

 are neither orbital nor temporal wings. The parietals, which 



