Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.2): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

634 FISHING DOG — COEALS. April almost like that of a turtle, within which are two rows of saw- like teeth. — Mr. Stokes saw a dog, (bred on the island), catch three such fish in the course of a few hours by chasing them in shallow water, springing after them, almost as a kangaroo springs on land. Sometimes one would take shelter under a rock, when the dog would drive it out with his paw, and seize it with his mouth as it bolted. Among the great variety of corals forming the walls around the immediately visible basement, and the under-water forests of the Keeling islands, there is more difference than between a lily of the valley and a gnarled oak. Some are fragile and delicate, of various colours, and just like vegetables to the eye, others are of a solid description, like petrified tropical plants ; but all these grow within the outer reef, and chiefly in the lagoons.* The wall, or outer reef, about which so much has been said and thought, by able men, without their having arrived at any definite conclusion, is solid and rock-like, with a smooth surface ; and where the surf is most violent, there the coral is fullest of animated matter. I was anxious to ascertain if possible, to what depth the living coral extended, but my efforts were almost in vain, on account of a surf always violent, and because the outer wall is so solid that I could not detach pieces from it lower down than five fathoms. Small anchors, hooks, grappling irons, and chains were all tried — and one after another broken by the swell almost as soon as we ' hove a strain' upon them with a ' purchase' in our largest boats. Judging however, from impressions made upon a large lead, the end of which was widened, and covered with tallow hardened with lime, and from such small fragments as we could raise, I concluded that the coral was not alive at a depth exceeding seven fathoms below low water. But this subject has been, or will be, fully discussed by Mr. Darwin, therefore I need say no more. * One kind of coral, while alive, stings human flesh painfully when touched by it. Another kind is so hard that it gives sparks when struck by steel.