98 CLASS REPTILIA. 



of generation is sometimes double, sometimes single, 

 according to the genera. 



All have a tail more or less long, and almost 

 always very thick at its base. The greater number 

 have four legs : some of them, however, have but 

 two. 



They form but two genera in the system of Lin- 

 naeus — the Dragons and the Lizards; but the last 

 should have been divided into many, which differ in 

 the number of the feet and of the genital organs, in 

 the forms of the tongue, tail, and scales, to such a 

 degree, that we are obliged to divide them into 

 many families. 



The first, or that of 



The Crocodilians, 

 comprehends but a single genus ; namely. 



The Crocodiles. Crocodilus. Br. 



They are of a great size ; have the tail compressed 

 laterally ; five toes before, and four behind, of which 

 the three internal alone are armed with claws on 

 each foot, but all are more or less united by mem- 

 branes. There is a single rank of pointed teeth in 

 each jaw. The fleshy tongue is flat, and attached to 

 the floor of the mouth as far as within a very little of 

 its edges, which led the ancients to believe that it 

 was altogether wanting. The penis is single ; the 

 aperture of the anus, longitudinal ; the back and tail 

 covered with large square scales, very strong, and 



