249 



be inferred the vast length to which these vertebral columns may have 

 been extended. 



In that part of the vertebral column of the lily encrinus which ap- 

 proaches to the pelvis, it was shewn, that a greater power of motion was 

 given by a peculiar arrangement of the vertebrae ; whilst security from 

 dislocation was also obtained, by the lapping of the edges of one ver- 

 tebra over those of the other. In this animal, a still greater latitude 

 of motion must have been yielded, by the extreme thinness, and of 

 course, greater number of the vertebrae, in this same part, as is seen, 

 Plate XVII. Fig. 15 : whilst a similar formation of the vertebrae is 

 observable, for the prevention of dislocation ; this appearing to have 

 been also guarded against, by the peculiar arrangement of those parts 

 which we shall next examine. These parts are the articulated ver- 

 tebral processes, which, as has been already observed, proceed from 

 every part of the vertebral column. 



Plate XVII. Fig. 16, shews the appearance yielded by these curi- 

 ously formed bodies, as proceeding from the vertebras. A single 

 ossicula of which, of a rhomboial form, from that part of these 

 processes which is nearest to the vertebrae, is shewn, Plate XVII. 

 Fig. 14, of its natural size, as well as slightly magnified. In these 

 figures are also seen the flat surfaces by which these ossiculae are 

 articulated. 



When commencing the examination of these bodies at their origin 

 from the vertebrae, Plate XVII. Fig. 16, a remarkable circumstance 

 immediately arrested the attention : these articulated processes 

 seemed to have passed out through the bodies of the thicker ver- 

 tebrae. But that this had not been the case, appeared to me to 

 be most reasonable to conclude, when I considered how much 

 readier a passage, apparently, must have been found by them, between 

 the vertebrae. Led by this consideration, I sought to discover the 

 openings by which they had proceeded : but after examining various 

 specimens, with the utmost attention; hoping to detect some of these 



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