84 ZOOPHYTES. 



that break over them. The microscopic germ of a Gorgonia developes 

 a polyp barely visible to the naked eye, which has the power of pro- 

 ducing a secretion from its base. The polyp buds, and finally the 

 growing shrub is covered with branches and branchlets, many a 

 mere thread in thickness, which stand and wave unhurt in the 

 agitated waters. The same secretions fix it to its support, and so 

 strongly, that even the rock comes away before the zoophyte will 

 break from its attachment. Tens of thousands of polyps cover the 

 branches, like so many flowers, spreading their tinted petals in the 

 genial sunshine, and quiet seas, but withdrawing when the clouds 

 betoken a storm. 



" Excelsior" is the grave motto of the zoophyte. Ever upward, 

 they continue growing and elongating, although death is at work 

 below, with as rapid progress. A beautiful provision protects the 

 branching coral-tree — often the work of ages — from being destroyed 

 by the dissolving waters, when exposed, on the death and removal of 

 the polyps. Certain minute incrusting corals — the Bryozoa and Ser- 

 tularidse, together witli NuUipores — make the surface their resting- 

 place, as soon as it is laid bare, and go on spreading and covering the 

 dead trunk, and so prevent the wearing action of the sea. The 

 Madrepore may thus continue to enlarge beyond its adult size; the 

 Caryophyllia may multiply almost endlessly its cylindrical branch- 

 ings, although the living animal but tips the extremities of each ; for 

 protection is given at once, when needed, and the polyps die, only to 

 leave the surface to other forms of life, more varied and no less strangfe. 



Finally, the coral becomes subservient to a still higher purpose 

 than the support of polyps and nuUipores. The debris, produced 

 by the waves over a reef, settles into the many crevices among the 

 dead trunks, and fills up the intervals, often large, between the scat- 

 tered coral-patches ; and, by this combined action of living growth 

 and detritus accumulations, a solid rocky basement is formed, and 

 kept in constant increase. In this way the coral-reef gradually nears 

 the surface, and finally becomes the foundation of one of the fairest of 



" The sea-girt isles, 

 That, like to rich and various gems, inlay 

 The unadorned bosom of the deep," 



the coral polyps now yielding place to the flowers and groves of the 

 land, which fulfil their end in promoting the comfort and happiness 

 of man. 



