character of the encrinus, the separation into a pentapetalous form, 

 begins to be displayed. In this body, the inferior surface, like that 

 of the vertebra?, possesses a regular concavity ; but its superior sur- 

 face is formed of five nearly triangular depressions, separated by 

 as many linear projections, passing from, the centr^ to the circum- 

 ference. 



From the form and situation of this body, it may 'fee considered as 

 analagous with those parts which, in the preceding encrinites, I have 

 considered as clavicles : the only difference being, that here they are 

 united in one piece, whereas in the former species they exist in five 

 separate pieces. This body, or clavicle, is represented separate, 

 Plate XVI. Fig. 4, united with the vertebrae at Fig. 7, and with the 

 other parts of the animal, Fig, 8, a. 



That formation of the solid parts, or of the skeleton of the animal, 

 next takes place, which we have already seen adopted, in the preced- 

 ing species, as preparatory to the formation of the limbs of the ani- 

 mal. Five separate bodies, externally of a rhomboidal form, with in- 

 ferior surfaces fitted to the superior surfaces of the bodies which have 

 been just mentioned, and with superior surfaces exactly resembling 

 their inferior, form the next series of solid parts, and which appear to 

 answer to those parts which in the preceding species we have consi- 

 dered as scapulae. These are represented, Plate XVI. Fig. 8, b. where 

 it will be also seen, that in the centre of the side of one of these, a fo- 

 ramen, and in that of another, a projection is observable, showing that 

 from these parts articulated processes had been given off, in the same 

 manner as from some of the trochitae already noticed. 



On the superior surfaces of these last-described bodies are placed 

 five others, which are the first series of those which may be considered 

 as forming the arms of the animal. The inferior surface of each of 

 these bodies forms an obtuse angle exactly agreeing with the angle 

 formed at the union of the preceding bodies, and in which angle 

 these bodies are disposed, whilst the superior surface is regularly 



