EEPTILES. 



297 



by one side of the fang to the 

 internal surface of the jaws. The 

 vertebral bones, and those of the 

 extremities, prove that this genus 

 attained gigantic dimensions. 

 (Fig. 201.) 



The figure of the tooth shows 

 the singular structure of the 

 crown, and how it was worn 

 down by attrition. The Iguano- 

 don was terrestrial and herbivo- 

 rous. (Fig. 202.) 



3rd Family. The LACEE- 

 TINID^: is composed of nume- 

 rous genera of living and ex- 

 tinct reptiles, which have the 

 lizards for their type. The ex- 

 isting genera are small ter- 

 restrial animals, but the ex- 

 tinct genera were of colossal 

 dimensions, and are supposed 

 to have been marine. We refer 

 to this family : 



The Protorosaurus, from the 

 Permian stage of Tubingen. 



The Thecodontosaurus and 

 Palceosaurus, from the dolomitic 

 conglomerate of Bristol. 



The Cladyodon, from the Keii- 

 per of Warwickshire. 



The Mosasaurws, from the chalk 

 of Maestricht, France, England, 

 and North America.* 



The Geosaurus, from the Oxford 

 stage of Solenhofen. 



The Leiodon, from the chalk of 

 Norfolk. 



The Rapliiosaurtis, from the 

 chalk of Cambridge. 



FIG. 201. 

 Left Femur of an Iguanodon. From 



Brook Bay. 

 (The original 40 inches in length.) 



a, Upper trochanter ; 5, middle tro- 

 chanter; c, inner; d, outer condyle; 

 e, groove between the condyles. 



* Pictorial Atlas, plate Ixx. 



