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part is, in this species, formed of three trigonal pieces, the two lower- 
most of which are very thin, and are applied by one of their sides to 
the vertebrae ; but the uppermost suddenly widens, so that the upper 
part of the surface, which is applied to the vertebral column, is 
exactly of the width of the vertebrae themselves.* On the summit of 
this body is a semilunar cavity, sloping outwards and downwards, 
in which a central foramen and a transverse ridge is observable. 
Between each of these scapulae, on each of the angles of the vertebral 
column, a small body, 5, is placed, which, from its assisting in 
attaching the scapula to the column, I consider, as I have done in 
the encrinites, as performing the office of a clavicle. The whole of 
these bones form the pelvis, in which the visceral part of the animal 
was, in all probability, deposited. 
Immediately on the semilunar cavity of each scapula is disposed the 
piece which forms the first joint of the arm of the animal, Plate XVII. 
Fig. 15, c; and on this is placed the second piece, d, the lower side 
forming the surface with which it articulates with the preceding piece, 
and the two upper sides forming the surfaces with which the two 
first pieces of a new series of ossiculae are articulated. At Fig. 13 is 
represented one of these ossiculae of its natural size, with its surface 
of articulation : and beneath it is a representation of the same body 
slightly magnified. 
The first ramification of the arms may be said to be completely 
dichotomous : but of the subsequent innumerable ramifications, a correct 
idea can only be obtained by a view of this part of the animal, or its 
representation, which has been endeavoured to be faithfully given, 
Plate XVII. Fig. 9j and Plate XVIII. Fig. 1. Another view of these 
parts is given, Plate XVIII. Fig. 2, where the ossiculae are denoted by 
* Were it not that it might have the appearance of aiming at too great a degree of 
nicety, and of labouring too much to make out the supposed analogy, I should have named 
the two lowermost of these bodies ribs, from the circumstance of their connexion with the 
vertebrae and the scapulae, and for the sake of preserving a greater degree of uniformity 
in the nomenclature. 
