[ 359 ] 
pable of bending at the will of the animal, in any 
dire&ion. 
If we examine the jive furrows or channels along 
the ftem, we fhall difcover a fmall hole between every 
vertebra, and in the center of the bafe of the lov ft, 
we fhall find a fmall hole there, which, probably, 
communicates through the middle of all the vertebrae 
to the cavity in the center of the head. 
Along this ftem, at different diftances, from an inch 
and quarter to a quarter of an inch in length, we ob- 
ferve many feries of five cylindrical-jointed arms, each 
feries is of equal length, and placed in a wheel or 
whirl-fhaped form like the equifetum or horfetail 
plant. Each arm is inferted in one of the five cavities 
of a vertebra, and each joint into one another ; that 
the upper end of one joint inclines over the lower end < 
of the next to it, which it appears, at the fame time, 
to inclofe with a fmall margin. 
Thefe joints are generally about one twelfth of an 
inch in length, and the fame in diameter, except a few 
near their infertion in the ftem, which are fhorter and 
thicker the nearer they are to it. 
We may plainly trace a fmall hole here through the 
midft of the joints, which communicates through the 
center of the ftarry vertebras in the main ftem, to the 
hooked joint at the extremity of thefe arms. 
On the under or inner fide of thofe joints, that are 
near the end of the arms, we may difcover four minute 
tubercles in every joint, two at each end ; thefe are of 
the fame teftaceous fubftance with the reft of the 
joint. By means of this uneven furfacc, together with 
the hook, which the laft joint forms, bending down- - 
wards, , 
