FOSSIL REPTILES. 289 



such differences consist in the number and form of the teeth, 

 which in many species are trenchant, and the number in the 

 intermaxillary unequal. 



The Lacerta teguixin, or American safeguard, is taken by 

 M. Cuvier as the type of the second family. 



Compared with the monitor of the Nile, the head is shorter 

 and less depressed. The muzzle is a little more raised. The 

 intermaxillary is also unequal ; but its nasal apophysis is much 

 shorter^ and instead of a single nasal, there are two large pe- 

 culiar bones of the nose which cover the greatest part of the 

 nasal cavity, so that the external osseous nostrils are small and 

 altogether towards the fore part of the muzzle. On the con- 

 trary, the principal frontal is single. The point of the edge of 

 the orbit appertains to the anterior frontal, and not to the 

 lachrymal, which is very narrow, and even not pierced. The 

 single lachrymal foramen is between the two bones, and below 

 it is seen a pterygopalatine foramen, or a posterior suborbital 

 one, formed between the anterior frontal, the palatine, the max- 

 illary, and the lachrymal. 



There is no foramen in the parietal. 



The jugal rejoins the posterior frontal and closes the frame- 

 work of the orbit. The descending laminae of the principal 

 frontal project very little. There is no suborbital ; but what 

 is very remarkable, the posterior frontal is divided by an ob- 

 lique suture into two bones, oneof which attaches only to the 

 frontal and parietal, the other to the jugal and temporal. 



Underneath, the intermaxillary, instead of forming a pro 

 cess behind, suffers an emargination there, and into this emar- 

 gination enter the points of the maxillaries and the vomeres. 

 The incisive foramina are extremely small. 



The lower cornets of the nose are ossified as in the Ouaran, 

 but they are not seen so easily in the head when entire, because 

 they are covered by the proper bones of the nose. But the 

 vomeres are shorter, wider, and not hollowed. The palatines 

 advance more, which renders the back nostrils more narrow. 



U 



