DISTRIBUTION OF FOSSIL CRINOIDEANS. 315 



The two most remarkable Genera of this famiiy have 

 been long known to Naturalists by the name of Encrinite 

 and Pentacrinite ; the former (see PI. 49, Fig. 1, and PI. 

 47, Figs. 1. 2. 5.) most nearly resembling the external form 

 of a Lily, placed on a circular stem ; the latter (see PI. 51, 

 and PI. 52, Fig. 1, 3,) retaining the general analogies of 

 structure presented by the Encrinite, but, from the penta- 

 gonal form of its stem, denominated Pentacrinite. A third 

 Genus, called Apiocrinites, or Pear Encrinite, (PI. 47. Figs. 

 1, 2.) exhibits, on a larger scale, the component parts of 

 bodies of this family ; and has been placed by Mr. Miller at 

 the head of his valuable work on the CrinoVdea, from which 

 many of the following descriptions and illustrations will be 

 collected. 



Two existing species of recent animals throw much light 

 on the nature of these fossil remains ; viz. the Pentacrinus 

 Caput Medusae from the West Indies, represented at PI. 52, 

 Fig. 1. and the Gomatula fimbriata,* figured in the first plate 

 of Miller's Crinoidea. 



We will proceed to consider the mechanical provisions 

 in the structure of two or three of the most important fossil 

 species of this family, viewed in relation to their office as 

 Zoophytes, destined to find their nourishment by spreading 

 their nets and moving their bodies through a limited space, 

 from a fixed position at the bottom of the sea ; or by em- 

 ploying the same instruments, either when floating singly 

 through the water, or attached, like the modern Pentelasmis 

 anatifera, to floating pieces of wood. 



Although the representatives of CrinoYdeans in our modern 

 seas of rare occurrence, this family was of vast numeri- 



* The Comatula presents a conformity of structure with that of the Penta- 

 crinite, almost perfect in every essential part, excepting that the column is 

 either wanting, or at least reduced to a single plate. Peron states that the 

 Comatula suspends itself by its side-arms from fuci, and Polyparies, and in 

 this position watches for its prey, and attains it by its spreading arms and 

 fingers. Miller, p. 182. 



