^37 
the narrow included vertebrae articulating with the inner crenulated 
surrounding edge or collar of the wider vertebrae. By this contrivance, 
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 admitting 
a certain degree of lateral motion, and at the same time presenting 
a check for the prevention of dislocation, manifest a curious con- 
trivance, 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. The fossil is com- 
posed of ten vertebrm closely conjoined ; each vertebrm having about 
one-third of its sides covered with a process divided into five denti- 
culfB, 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 contour 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- 
