and unequal surface ; being beset with knobs, which are the com- 

 mencement of so many radicles. 



The vertebrae terminate in the body above alluded to, as the infe- 

 rior termination of this encrinite. It has been accidentally broken, 

 but in the most desirable manner ; since the fracture having been 

 made longitudinally through its middle, its central structure is fully 

 displayed. We thus also perceive eight very thin and very finely ere- 

 nated vertebrae, over which a thin coat appears to be extended, which 

 is likewise extended over various tubular radicles, which ramify and 

 diverge in every direction around the vertebral trunk. In one part, 

 one of these radicles is seen, so fractured as to shew its crenulated 

 articulations, the crenulae, however, being so exceedingly shallow 

 that they could have yielded little or no capacity for motion. In the 

 other part of this radicle, the substance is considerably contorted ; 

 several projections, with a foramen in the centre of each, are seen on 

 its surface, and the articulations are so obliterated, as plainly to shew 

 that no motion could here have taken place. 



The nature and uses of the parts just described are clearly ascer- 

 tained by the extraordinary and unique specimen, Plate XV. Fig. 5, 

 which, from the purity and whiteness of the calcareous matter of the 

 organic part, and from the colour and other sensible qualities of 

 the matrix in which it has been imbedded, there is no doubt was 

 also obtained from Wenlock Edge. 



Extreme thinness of the vertebrae, it has been already observed, 

 appears to be one of the characteristics of this species of encrinite ; 

 and, in this specimen, this character is very observable ; since although 

 the trunk, from which the roots proceed, is only about an inch in 

 length, upwards of thirty vertebrae enter into its formation. These 

 vertebrae exactly resemble those of the column, in the mass alrea- 

 dy noticed, in their articulations being so little crenulated, that 

 they have been evidently capable of little or no motion; and, in their 

 being, in the same manner, beset with numerous projections ; each 



