24 J. D. Dana on Zoophytes. 
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 up- 
ward, 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 co- 
rals—the Bryozoa and Sertularide, together with Nullipores— 
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 
formed, and kept in constant increase. In this way the coral 
reef gradually nears the surface, and finally becomes the founda- 
tion 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 yield place to the flowers and groves of 
the land, which fulfill their end in promoting the comfort and 
happiness of man. 
Note.—The figures illustrating this article represent the following species of 
orals. 
Fig. 13. Polyp of the Mussa cactus (D), natural size. Allied to the Caryophyl- 
lia carduus of Lamarck, (genus Lobop) ye of Blainville.) tyt 
Fig. @a purpurea (D), alive and expanded ; natural size, 
Fig. 15. Part of a branch of the Madrepora cribripora (D), alive and expanded; 
natural size. § 
Fig. 16. Part of a branch of the Dendrophyllia nigrescens (D), alive and ex- 
panded; natural size. 
_ Fig. 17. A lobe of the Xenia florida, probably the Actinantha florida of Lesson ; 
natural size. 
Fig. 18. A polyp of the Tubipora fimbriata (D), enlarged between three and 
four diameters. 
Fig. 32. Caryophyllia arbuscula. (Lesueur.) 
Fig. 34. Part of a branch of Oculina varicosa. (Lesueur.) 
Fig. 35. Part of a branch of Oculina pallens. ( Ehrenberg.) 
Fig. 38. A branch of the Caulastrea furcata. (D.) 
