Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/319

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The two most remarkable Genera of this family have been long known to Naturalists by the names of Encrinite and Pentacrinite; the former (see Pl. 49, Fig. 1, and Pl. 47, Figs. 1. 2. 5.) most nearly resembling the external form of a Lily, placed on a circular stem; the latter (see Pl. 51, and Pl. 52, Fig. 1, 3,) retaining the general analogies of structure presented by the Encrinite, but, from the pentagonal form of its stem, denominated Pentacrinite. A third Genus, called Apiocrinites, or Pear Encrinite, (Pl. 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 Crinoïdea, 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 Medusæ from the West Indies, represented at Pl. 52, Fig. 1, and, the Comatula fimbriata, figured in the first plate of Miller's Crinoïdea.

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 employing 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 Crinoïdeans in our modern seas are of rare occurrence, this family was of vast numerical