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 
approaches 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 
vertebra 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 vertebral 
processes which, as has been already observed, proceed from every part 
of the vertebral column. 
Plate XVII. Fig. l6, shews the appearance yielded by these curi- 
ously formed bodies, as proceeding from the vertebrae. A single 
ossicula of which, of a rhomboidal 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 ossiculas 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 
VOL. II. K K 
