PLATE XIII. 



Fig. 1. EXTRACRINUS LEPIDOTLS. «, tO k. 



1, a. — lateral view of a well preserved specimen, which exhibits the rays, and the 

 plates which covered the plated membrane between the leading and principle rays. 



1, b. — a portion of column, with the side arms attached, and shewing the manner in 

 which they are inserted, right and left alternately. 



1, c. — enlarged lateral view of the body, exhibiting the prolonged jointed lateral pieces, 

 the way in which the rays are attached to them, with the scale-like plates 

 which connect the lower portions of the rays to each other, and also a portion 

 of the column. This figure is taken from the reverse or under side of the 

 specimen figure 1, cL 



1, d. — this figure exhibits nearly the same points as the preceding one, it is drawn in 

 the position it occupies on the upper side of the slab, but the pieces connecting 

 it with the rays, are displaced and broken. 



1, e. — an enlarged view of a portion of the column, shewing the manner in which the 

 claspers are inserted into the thickest joints. 



\,f. — the articulating surface of a columnar joint. 



1, g. — lower joints of the first divisions of the rays. 



1, h, — cuneiform joint at the first bifurcation. 



1, /. — portion of a column of the natural size. 



1, k. — an enlarged view of a portion of the rays, with the intervening plates. 



PLATE XIV. 



Fig. I. Pentacrinus caput Medus.e. a, to f. 



1, a. — lateral view of a beautiful specimen from the Caribbean sea, at present in the 

 Bristol Institution. The drawing represents the lower portion of the body, the 

 the rays, the tentacula, the column and auxiliary side arms or claspers. The 

 figure is exactly half the natural size, and although some of the rays in the 

 specimen have fallen asunder, (as shewn in the drawing,) owing to the difficulty 

 of preserving the connecting integuments from decay, it is sufficiently perfect to 

 exhibit all the essential parts of the animal, except the plated membrane, which 

 covered the digestive organs. 



