90 
near the base, showing at the circumference a swelling out of the surrounding 
muscular covering, forming more or less regular and conspicuous tubercles 
perforated at their summit. These are sometimes elongated into fibres, branch- 
ing and dividing at intervals. The tubercles have at their summit a round per- 
foration, which extends through their middle when they are elongated into fibres. 
It is difficult to explain of what utility they are to the animal, unless we consider 
them as secreting tubes, or as feelers by which the animal might have explored 
substances near it. 
The Base. (fig. 4.) The elongated subdividing fibres proceeding abun- 
dantly from the lowet portion of the column, form a kind of fascicular or rather 
root-like base, and where two or more individuals occur near each other, these 
fibres appear to have lost their muscularity, to have exuded calcareous matter, 
or become themselves gradually converted into it ; and being no longer of utility 
tothe animal in ‘any other'way, they have become connected with the contiguous 
individuals, forming with them one substance (fig. 3.) the animals so uniting, in 
consequence losing their locomotive power. 
The Petvis is formed of five plates, is hollowed out at the bottom for the 
reception of the upper columnar joint, adhering to it by its radiatingly striated 
surface, and perforated in the centre for the pentapetalous passage of the ali- 
mentary canal. The outer rim of its five plates bends upwards, forming a sort 
of saucer, each plate being angularly pointed at its superior edge. 
The Five Cost are inserted in the angular spaces formed by the pelvis, 
four of them are hexagonal, and one is heptagonal, having its summit partly 
truncated, to which a small hexagonal plate adheres. 
‘The Scapuxz are inserted in the angles formed at the upper edge by the 
coste, having at their summit a horse-shoe-lke depression for the articulation 
of the arm joints. 
I have not seen a specimen by which I could ascertain the form of the arins, 
fingers, and tentacula; but believe them in general form, analogous to those of 
the former species, possessing also the muscular plated integument. 
Externally the outer surface of the portion of the plates of the pelvis where 
they are turned up, the cost and scapule (fig. 1.) are marked by rugged strix. 
