FLORIDA REEFS. . ' 23 



selves. Living in communities, death begins first at the base or centre 

 of the group, while the surface or tips still continue to grow, so that it 

 resembles a dying centennial tree, rotten at the heart, but still apparently 

 green and flourishing without, till the first heavy gale of wind snaps the 

 hollow trunk and betrays its decay. Again, innumerable boring animals 

 establish themselves in the lifeless stem, piercing holes in all directions into 

 its interior, like so many augers, dissolving its solid connection with the 

 ground, and even penetrating far into the living portion of these compact 

 communities. The number of these boring animals is quite incredible, and 

 they belong to different families of the animal kingdom : among the most 

 active and powerful we would mention the date-fish, Lithodomus, several 

 Saxicava, Petricola, Area, and many worms, of which the Serpula is the 

 largest and most destructive, inasmuch as it extends constantly through the 

 living part of the coral stems, especially in Maeandrina. 



On the loose basis of a Maeandrina, measuring less than two feet in 

 diameter, we have counted not less than fifty holes of the date-fish, — some 

 large enough to admit a finger, — besides hundreds of small holes made 

 by worms. 



But however efficient these boring animals may be in preparing the 

 coral stems for decay, there is yet another agent, perhaps still more 

 destructive. We allude to the minute boring-sponges, which penetrate 

 them in all directions, until they appear at last completely rotten 

 throughout. 



The outer reef, or, as it is generally called on the spot. The Reef, is the 

 main seat of the present activity and growth of the reef-building corals in 

 Florida. This reef consists of a narrow wall, rising nearly to the surface of 

 the water, with a steep seaward slope, and a gentler one on the inner side 

 toward the ship-channel. Its greatest width varies from one to two miles, 

 though it is frequently not more than half a mile wide. This is true, for 

 instance, of all those narrow ledges which have risen to within a few feet of 

 the surface, such as Fowey Eocks off Soldier Key, Triumph Reef off 

 Ragged Key, Long Reef off Elliott's Key, Ajax Reef off Caesar's Creek, 

 Pacific Reef off Old Rhodes, Turtle Reef off the eastern extremity of Key 

 Largo, and the extensive reef of Carysfort facing for several miles Ke^^ 

 Largo. This spot is one of the most instructive on the reef Here the reef, 

 for a stretch of several miles, nearly reaches the surface and forms a long 

 level ledge entirely covered with living corals (chiefly the large spreading 



