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. 



