UPPER, OR FLINTY CHALK. 181 



ENCKIKITES AND PENTACRIKITES *. 



This name has long been applied to the petrified skeletons of those 

 zoophytes that possess a pelvis or basin, composed of an immense number 

 of crustaceous articulated plates, and ossiculas f , supported by a jointed 

 flexible column. 



The pelvis, which originally contained the viscera of the animal, is 

 surrounded by long jointed arms or tentaculae, and affixed to the ver- 

 tebral column, by a pentagonal plate placed in the centre of the base. 



The column, in most species, is of an immense length, and consists of 

 separate joints or vertebrae, regularly united, pierced in the centre, and 

 liaving their articulating surfaces ornamented with radiating, stellular, 

 or floriform markings. The inferior part of the column has a pedicle, 

 or process of attachment, by which the animal was fixed to other 

 substances :]:. 



In the recent state, the skeleton was in all probability clothed with 

 a fleshy, or coriaceous integument ; the central perforation in the ver- 

 tebral column, is supposed by Mr. Martin, to have been filled with a 

 medullary substance, by which sensation was conveyed to the inferior ex- 

 tremities of the animal § ; but according to ^Ir. Miller, it served as an 

 alimentary canal ||. 



The detached vertebrae are known to collectors by the name of 

 trochita ; and when several are united together, so as to form part of a 

 column, the series is termed an entrochite. 



The remains of this family of zoophytes, so rarely occur in the chalk 



* In the enc7-inites, the bones of the vertebral cohimn are circular or elliptical ; in the penta- 

 crinites they are angular or pentagonal. 



f Mr. Parkinson has shewn, that upon a moderate calculation, the lily encrinite must have 

 been composed of nearly thirty thousand distinct bones. Org. Rem. Vol. ii. p. 181. 



X For a more particular account of the natural history of this extraordinary tribe of animals, 

 consult the ;2d vol. of Parkinson's Organic Remains ; and Millers Natural History of the Cri- 

 jwidea, or, Lily -shaped Animals ; 1 vol. 4to. 1821; a work that has been justly characterized by 

 an eminent writer, as "a model of patient, sagacious, and successful research." 



§ Martin s Syst. Arrangement, p. 209. 



II Miller's Crinoidea, p. )1. 



