Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/332

 328 succession of teeth, set at minute intervals from one another, and locking into the interstices between corresponding teeth on the surface of the next vertebrae, they are so disposed as to admit of flexure in all directions, without risk of dislocation.

As the base or root of Pentacrinites was usually fixed to the bottom of the sea, or to some extraneous floating body, the flexibility of the jointed column, which forms the stem, was subservient to the double office, first, of varying, in every direction, the position of the body and arms in search of food, and secondly, of yielding, with facility, to the course of the current, or fury of the storm, swinging, like a vessel held by her cable, with equal ease in all directions around her moorings.

The Root of the Briarean Pentacrinite was probably slight, and capable of being withdrawn from its attachment. The absence of any large solid Secretious, like