284 FOSSIL REPTILES. 



The palatines have no palatine laminae, or, at least, these 

 laminae are not sufficiently extended to unite ; and the hinder 

 osseous nostrils are large holes in the anterior part of the vault 

 of the palate, between the maxillaries^ the vomer, and the 

 palatines. 



Such are the principal peculiarities of the headoflacerta, in 

 general, and all that are necessary to be noticed here. 



This family is sub-divided into two tribes, in relation to the 

 composition of the muzzle : that of the monitors of the an- 

 cient continent, which have but a single nasal and two princi- 

 pal frontal bones, and those American lizards, such as the 

 bicarinafa, teguixin, ameiva, &c. of Linnaeus, and which are 

 termed sauvegardes, by M. Cuvier, and other French natu- 

 ralists. This sub-division embraces most of the other genera 

 of Saurian reptiles, and the animals comprised therein have 

 two nasal and one principal frontal bone. 



The first family comprises only the monitors of the old 

 continent, with small scales under the belly, and on the tail. 

 We shall consider, as an example of this, the great Monitor of 

 the Nile, (^Lacerta Nilotica,) called Ouaran by the Arabs. 



The general conformation of the head is that of an 

 elongated cone, depressed, blunt at the point, with the anterior 

 frontal and parietal region plane. The orbits are round, and 

 pretty nearly in the middle of each side. The external osseous 

 nostrils rise almost to the elevation of the orbits. 



There is but one inter-maxillary widened in front, where it 

 has four teeth on each side, and mounting by a long com- 

 pressed apophysis as far as towards the middle of the nostrils, 

 where it unites to what represents the nasal bone. This is 

 also equally uneven, widening in the top, and there bifurcating 

 to unite itself to the two frontals. These occupy their usual 

 space between the orbits, and have, each of them, underneath, 

 an orbital lamina, which approaches and unites to its cor- 

 responding one, to complete the canal of the olfactory nerves. 

 The maxillaries embrace in front, by a depressed part, the 



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