237 



the narrow included vertebrae articulating with the inner crenulated 

 surrounding edge or collar of the wider vertebrae. By this contriv- 

 ance, a degree of flexibility was secured, proportionate to the extent- 

 to which the several vertebrae were capable of obliquely moving on 

 each other. 



In the specimen now under examination, a similar arrangement is 

 observable through its whole extent. Narrow and wider vertebrae, 

 with the former included in the margin of the latter, thereby admit- 

 ting a certain degree of lateral motion, and at the same time present- 

 ing a check for the prevention of dislocation, manifest a curious 

 contrivance, and leads us to the conclusion, that, in this part of the 

 animal, the power of performing this kind of motion was particularly 

 demanded. 



To explain the uses of the digitated processes, given off from the? 

 wider and larger vertebrae, and which, in its present lapideous state, 

 connects in several parts the opposite windings of the column, I ac- 

 knowledge myself entirely incompetent. I am equally incapable of 

 forming any opinion with respect to the other parts of this animal ; 

 not ever having seen any part which appeared at all to correspond 

 with it, in its peculiar and extraordinary conformation. 



How far this last assertion requires an excepting clause in favour 

 of the fossil, Plate XVI. Fig. 9> I will leave you to determine, after 

 having attended to its form and appearance. This fossil is com- 

 posed of ten vertebrae closely conjoined ; each vertebras having about 

 one third of its sides covered with a process divided into five denti- 

 culae, which are placed at regular and accordant distances in each 

 vertebra. The other two- thirds of the sides of the vertebrae are very 

 closely beset with small points and tuberculae, almost linearly dis- 

 posed, and giving to the surface a very uncommon and indescribable 

 appearance. Indeed the extraordinary form and con tour of the whole 

 fossil is so difficult to describe, as to render a reference to the an- 

 nexed figure indispensably necessary to its comprehension. Except- 



