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 around 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 lower 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 

 to the 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 PELVIS 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 COSTJE 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 SCAVULJE are inserted in the angles formed at the upper edge by the 

 costa?, having at their summit a horse-shoe-like depression for the articulation 

 of the arm joints. 



I have not seen a specimen by which I could ascertain the form of the arms, 

 fingers, and tentacula; but believe them in general form, analogous to those of 

 the former species, possessing also the muscular plated integument. 



Externally the oufer surface of the portion of the plates of the pelvis where 

 they are turned up, the costse and scapulae (fig, 1.) are marked by rugged striae. 



