The dynamiting work is, perhaps, the most fascinating of the collecting activities of the Albatross. Through the small, square, pane of the water glass, one sees the rough and jagged ledge of coral, gray or brown in the background, with encrusting forms of blue, purple, sea-green, brown, orange and varying shades of red and pink. The ledge is shattered and honeycombed into an intricate maze of crevices and pinnacles—a broken and rugged floor mottled with irregular patches of color. Huge masses of fluffy, gray soft-coral are mingled with beds of crinoids moving their long, chrysanthemum-like arms to and fro with the ground motion of the swell. Points of rock protrude among these uneven garden plots or are partially hidden by the waving masses of hydroids. Here, a delicate sea-fan stands erect upon a rocky corner; a spotted crab runs from one hiding place to another; and a great, blue starfish sprawls over a bare rock. There, a sea-cucumber, like a stout serpent, halts in the middle of a patch of sand; and among the rocks rest the giant clams with their wide open velvety mouths. A cluster of little anemones gaze upward in astonishment, and a sea-urchin huddles into a crack, like a porcupine searching for grubs among logs.
The coral usually grows out from the shore as a fringing reef, often forming a table or a coral shelf with only a few feet of water above it, and ending abruptly in a coral cliff. There are found the most luxuriant growths, as the bottom rapidly recedes from a depth of one or two fathoms to a depth of ten or fifteen fathoms, beyond which the eye, aided even with the water glass and the brightest sunlight, can not penetrate. These are the reefs of solid coral formation.
Around other islands, the coral is merely an incrustation on the rocky ledges which form the island. Occasionally a locality is found like that of the volcanic island of Kagayan Sulu, where the coral which once flourished has been killed, possibly by some change in the ocean currents or by a volcanic uplift of the island. The finer structures have been worn away and the bases of the clumps of coral stone are now covered with the slime of a fine, brown alga.
The next reef visited may be farther up the bay and bear a character very different from that of the reefs on the exposed points. Huge, goblet-shaped sponges of a living gray color stand up motionless on their thick stalks between great tables of spiny coral borne on pedestals, each little spine on these tables looking like one of the trees on a wide, pineforested plateau. Beautiful brown plate corals and shelf corals hang along the walls of the ledges.
Another type of coral, growing sparsely over a sandy bed, may be the last representative of the coral animal to be found well inside the bay. The growth consists of hedges and patches of the diffuse and intricate tangle of branching, stag-horn corals. Scattered among the brown sea-grasses between these hedges which parallel the shore are