ON THE SKELETONS OF ZOOPHYTES. 
182 
the abode of an isolated gigantic Polyp. The development of the skeletons of 
Lithophytes is due to the enveloping organised fleshy crust which deposits suc¬ 
cessive layers of the albumino-calcareous material by which the stony fabric of 
these simple beings expands in all directions. Like the horny axis of Gorgonice , 
or the shells of Mollusca , they are altogether extravascular, and consequently 
inorganic; no interstitial absorption being possible in these massive Calcareous 
habitations, it is from this law of their economy that the Polypifera have played 
so important a part in the seas of all periods of our planet’s history. Their 
microscopic operations have ever been the same, to crowd their silent waters with 
myriads of living forms, ornamented with the most beautiful and brilliant hues, 
and tending by their ever-aetive carnivorous propensities to keep a vigilant check 
on the inordinate increase of Infusoria , which teem in every drop of the vast 
abyss, whilst the incessant increase of their Calcareous habitations, which cover 
almost every rock, sub-marine ridge, and volcanic cone, in tropical seas, tends to 
build up from the bosom of the deep Calcareous strata many hundreds of 
miles in extent. It is thus that a knowledge of the organisation and living 
habits of this class becomes an important and interesting branch of philosophical 
Geology, and illustrates the intimate connexion which subsists between the 
physical history of the earth and the myriads of living forms that adorn its 
varied surface. 
The rising of oceans in these latitudes elevates above the waters a living 
hill of zoophytes, whose enduring skeletons are destined to become the theatre of 
a new series of phenomena; thus raised above the surface of the water and 
exposed to the action of the atmosphere, and the washing of the surge, the Coral 
isle becomes covered with a fertile soil, into which seeds wafted by the winds, or 
deposited by birds which find, on this new-born rock, a temporary resting-place 
in their migratory voyage to some far distant land; by these and other agents 
this infant isle soon becomes clad with a luxuriant vegetation, and this sepulchre 
of Polypifera is thus converted into verdant land, fit for the habitation of Man. 
The observations of recent voyagers, as Quoy, Gaimard, Stuchbury, and 
Darwin, have shewn that the labours of Lithophytes commence only at incon¬ 
siderable depths from the surface, and that for the most part recent Madreporic 
strata are due to the living energies of Meandrina , Astrea , Caryophyleia , and 
Madrepora. This fact affords a striking illustration of the universality of the 
laws which regulate the development and distribution of animal life; for through¬ 
out the entire series of fossiliferous rocks, wherever we discover Coralline strata 
to such an extent as would justify the inference that they formed part of an 
ancient Coral-reef, we find, on investigation, that such rocks are almost entirely 
composed of extinct species of the same genera of zoophytes that at the present 
