Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/335

 STOMACH, BODY, ARMS, AND FINGERS OF PENTRACRINITE.

The abdominal cavity, or stomach, of the Pentacrinite, (Pl. 51, Fig. 2.,) is rarely preserved in a fossil state; it formed a funnel-shaped pouch, of considerable size, composed of a contractile membrane, covered externally with many hundred minute calcareous angular plates. At the apex of this funnel was a small aperture, forming the mouth, susceptible of elongation into a proboscis for taking in food. The place of this organ is in the centre of the body, surrounded by the arms.

The body of the Pentacrinite, between the summit of the column and the base of the arms, is small, and composed of the pelvis, and the costal, and scapular plates, (See Pl. 51. Pl. 52. Fig. 1. 3. and Pl. 53. Fig. 2. 6. E. F. H.) The arms and fingers are long and spreading, and have numerous joints, or tentacula; each joint is armed at its margin with a small tubercle, or hook, (Pl. 53. Fig. l7.,) the form of which varies in every joint, to act as an organ of prehension; these, arms and fingers, when expanded, must have formed a net of greater capacity than that of the Encrinites.

We have seen that Parkinson calculates the number of bones in the Lily Encrinite to exceed twenty-six thousand.