§ 35. 



DINOSAUR IAXS. 



419 



35. Dinosauriaxs.*— We now arrive at the consideration 

 of three genera of extinct saurians or lizards, the Megalo- 

 saurus, Iguanodon, and Hylaeosaurus, which are so essen- 

 tially different in their osteological characters from all other 

 known types, as to constitute a distinct order, that unites the 

 lacertian with the crocodilian oviparous quadrupeds. The 

 remains of these animals are principally distributed in the 

 Wealden deposits ; but of the first, the most interesting 

 relics have been obtained from the Stonesfield slate, which 

 is situated in the lower division of the Oolite : and of the 



confers the power of free motion without risk of dislocation or muti- 

 lation. The importance of a knowledge of this fact to the palaeonto- 

 logist is too obvious to require remark ■ the discovery in the wealden 

 of a caudal vertebra, having both the extremities convex, would, I 

 must confess, have been very perplexing, previously to mv detection 

 of this peculiarity of structure in the recent Gavial. 



LlGS. 100.*— SACRAL AND CAUDAL VERTEBRA OE THE GAVIAL- 



Figs. 1. 2. The two anchylosed sacral vertebra. 3. The first caudal or coccygeal 



vertebra, which is doubly convex. 



* Dinosaurians, signifying fearfully great Lizards: a term 

 employed by Professor Owen to designate an order of extinct terres- 

 trial reptiles, which comprises the Iguanodon, Megalosaurus. and 

 Hylaeosaurus. It is to be regretted that some other name was not 

 chosen; for the occurrence of the same word (fords, deinos) in Dino- 

 therium (ante, p. 173), Dinornis (ante, p. 129), &c. suggests to the 

 unscientific reader, an erroneous idea of an affinity between these 

 extinct reptiles, mammals, and birds, which it was desirable to avoid" 

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