LILY ENCRINITE. 423 
We will first examine the contrivances in the 
joints, of the vertebral column, which adapted it 
for flexure in every direction, and then proceed 
to consider the arrangement of other parts of the 
body. 
These joints are piled on each other like the 
masonry of a slender Gothic shaft, but, as a cer- 
tain degree of flexibility was requisite at every 
articulation, and the amount of this flexure varied 
in diflerent parts of the column, being least at 
the base and greatest at the summit, we find pro- 
portionate variations both in the external and in- 
ternal form and dimensions of each part.* The 
* The body (PI. 49, Fig. 1) is supported by a long vertebral 
column attached to the ground by an enlargement of its base (PI. 
49, Fig. 2). It is composed of many cylindrical thick joints, 
articulating firmly with each other, and having a central aper- 
ture, like the spinal canal in the vertebra of a quadruped, through 
which a small alimentary cavity descends from the stomach to 
the base of the column, PI. 49, Fig. 4, 6, 8, 10. The form of 
the column nearest the base is the strongest possible, viz. cylin- 
drical. This column is interrupted, at intervals, which become 
more frequent as it advances upwards, by joints of wider diameter 
and of a globular depressed form (PI. 49, Fig. 1. and Figs. 3,4, 
a, a, a, a.) Near the summit of the column, (PI 49, Figs. 3, 4,) 
a series of thin joints, c, c, c, is placed next above and below each 
largest joint, and between these two thin joints, there is intro- 
duced a third series, b, b, b, of an intermediate size. The use 
of these variations in the size of the interpolated joints was to give 
increased flexibility to that part of the column, which being near- 
est to its summit required the greatest power of flexion. 
At Plate 49, Figs. 6, 8, 10, are vertical sections of the 
columnar joints 5, 7, 9, taken near the base; and show the in- 
ternal cavity of the column, to be arranged in a series of double 
