Lign. 15:—Branch of Coral on the Pebble.
| Fig. | 1.— | A portion magnified. |
| 2.— | A fragment represented as when alive. a, a, Two polypes collapsed. b, b, Two polypes with their tentacula extended. |
One more character inscribed on the pebble remains to be interpreted; it is the minute branch of coral partially imbedded in the flint.[P] The surface of this coral, when seen with a powerful lens, is found to be studded with small pores or cells. In a recent state, each cell was inhabited by a living polype or animalcule, which, though permanently united at its base to the general mass, had an independent existence, and possessed sensation and voluntary motion; expanding its thread-like feelers or tentacula to catch its prey, and withdrawing, at will, into its little cell.[Q]
[P] [Plate I] immediately below the shell and spine of Echinus.
[Q] For a popular account of recent and fossil corals, see 'Wonders of Geology,' 6th Edit., vol. ii. Lecture VI. p. 589.
Lign. 16:—A Coral-polype preserved in flint: magnified 500 diameters.