MECHANICAL CONTRIVANCES IN ENCRINITES. 425 
parts of England they still retain the appellation 
of St. Cuthbert's beads. 
On a rock by Lindisfarn 
Saint Cuthbert sits, and toils to frame 
The sea-born beads, that bear his name. 
Marmion. 
Each of these presents a similar series of arti- 
culations, varying as we ascend upwards through 
the body of the animal, every joint being exactly 
adjusted, to give the requisite amount of flexi- 
bility and strength. From one extremity of the 
vertebral column to the other, and throughout 
than the plane crenulated surfaces near the base of the column, 
Figs. 9, 10, and at the same time renders dislocation almost im- 
possible. 
To these is superadded a third contrivance, which still further 
increases the flexibility and strength of this portion of the column, 
viz. that of making the alternate larger joints, b. b. considerably 
thinner than the largest collar joints, a. a. 
The Figures numbered from 11 to 26 inclusive, represent 
single vertebrae taken from various portions of the column of 
Encrinites moniliformis. The joints at Figs. 11, 13, 15, 17, 19, 
21, 23, 25, are of their natural size and in their natural hori' 
zontal position, and show, at the margin of each, a crenated edge, 
every tooth of which articulated with a corresponding depression 
near the margin of the adjacent joint. The stellated figures 
(12, 14, 16, 18, 20, 22, 24, 26,) placed beneath the horizontal 
joints to which they respectively belong, are magnified repre- 
sentations of the various internal patterns presented by their 
articulating surfaces, variously covered with an alternate series 
of ridges and grooves, that like the cogs of two wheels, articulate 
with corresponding depressions and elevations on the surfaces of 
the adjacent vertebrae. 
