322 STRUCTURE OF CRINOIDEANS. 



From the subjoined analysis of the compotent portions of 

 the body of the E. MoniUformis, we see that it may be 

 resolved into four series of plates each composed of five pieces, 

 and bearing a distant analogy to those parts in the organiza- 

 tion of superior animals from which they have been denomi- 

 nated. A similar system of plates, varying in number and 

 holding the same place between the column and the arms of 

 the animal, may be traced through each species of the family 

 of Crinoi'deans. The details of all these specific variations 

 are beautifully illustrated by Mr. Miller, to whose excellent 

 work I must again refer those who are inclined to follow 



Figs. 1, 2. In Mr. Miller's restoration of the Pear Encrinite (PI., 47, Fig. 1) 

 tliey are represented as expanded in search of food. These tentaculated 

 fingers, when thus expanded, would form a delicate net, admirably adapted 

 to detain Acalaphans, and other minute molluscous animals that might be 

 floating in the sea, and which probably formed part of the food of the Cri- 

 noidea. In the centre of these arms was placed the mouth (PI. 47, Fig. 1.) 

 capable of elongation into a proboscis. Pi. 47. 6, x. 7, x. represent the 

 bodies of Crinoidea from which the arms liave been removed. 



In Pi. 50, Fig. 1 represents the superior portion of the animal, with its 

 twenty fingers closed like the petals of a closed lily. Fig. 2 represents the 

 same partially uncovered, with the tentacula still folded up. Fig. 3 is a side 

 view of one of the fingers with its tentacula. Fig. 4 represents the interior 

 of the body which contained the viscera. Fig. 5 represents the exterior of 

 the same body, and the surface by which the base articulates with the first 

 joint of the vertebral column. Figs. 6, 7, 8, 9, represent a dissection of the 

 four series of plates that compose the body, forming successively the scapulae, 

 upper and lower costal plates, and pelvis of the animal. Fig. 10 is the upper 

 extremity of the vertebral column. Fig. 11 represents the upper surfaces of 

 the five scapulae, showing their articulations with tiie inferior surfaces of the 

 first bones of the arms. Fig. 12 is the inferior surface of the same series of 

 scapular plates, showing their articulations with the superior surfaces of the 

 upper or second series of costal plates, Fig. 13. Fig. 14 is the inferior surface 

 of Fig. 13, and articulates with the first or lower series of costal plates, Fig. 

 15. Fig. 16 is the lower surface of Fig. 15, and articulates with the upper 

 surface of the bones of the pelvis. Fig. 17. Fig. 18 is the inferior surface of 

 the pelvis, Fig. 17. and articulates with the first or uppermost joint of the 

 vertebral column, Fig. 10. 



