130 
NATURAL HISTORY. 
[n. ZOOL. GAL, 
or of an expanded frondose mass, like the Fxplanaria. All these 
variations result from the manner in which the animal emits from the 
whole surface, or from a particular part of the sides of its body, the bud 
by which the new individuals of the general mass or society are pro¬ 
duced. 
In the greater part of these animals, the stomach is furnished with 
numerous folds, leaving many plates in the cells of the coral, and the 
mouth has generally equally numerous tentacles, as in the Sea Anemonies, 
or Actiniae. In some, as the Fungia , Turbinolia, and Cyathina , 
(Case 2,) the animals are simple and solitary, and not spontaneously 
divided, so that the coral only offers a single cell. In others, where 
the animals live in societies, the mouth often contracts on the side and 
separates of its own accord gradually into two or more mouths ; it then 
produces as many separate cells, which are separated or forked where 
the contraction took place. In some of these, as the Lobophyllia , &c., 
(Case 3,) the bodies of the different animals of the same mass, and the 
cells of the coral remain separate from each other. In a few, as 
Anthophyllum , ( Case 7,) at certain intervals of its growth, the animals 
throw out an expansion which deposits a shelly plate that unites the 
different cells formed by each of the bodies into a common mass, though 
the cells themselves are distant from each other. But in very many, 
the bodies of the different animals of the same group, as they are pro¬ 
duced, are united together side by side, forming a coral with all the cells 
united together into a globular, branched, or expanded foliaceous mass. 
These forms depend on the manner in which the reproduction of the 
different individuals of the masses takes place, whether by the con¬ 
traction and spontaneous division of the mouth, when the cells are deep 
and form a rounded mass, or by the developement of buds from the 
sides of the parents, when the animal forms an expanded frond, as in 
Pavonia , &c. 
In some, the stomach of the animal is only provided with twelve slight 
folds, and the mouth has only ten or twelve tentacles. In this case the 
cell of the coral is provided with only a few slightly raised rays. Most of 
these animals live crowded together in societies forming a branched 
coral, and the cellular substance of the animal is in general not so per¬ 
fectly filled with calcareous matter as in the former kinds; consequently 
the coral is of a more spongy or lighter texture, as in the Madrepores, 
Madrepora , Porites , &c. (Cases 15—18.) 
Near these Corals must be arranged for the present, until their 
animals are better known, the Millepores (Millepora alcicornis of 
Linnaeus). The latter is remarkable for the rapidity of its growth, and 
the facility with which it expands itself over all the different anomalous 
objects that come in its way ; thus we have it covering shells, bottles, 
gorgoniae, &c., and assuming the form of all the things it covers ( Case 
20). According to Mr. Nelson, the animal is very different from that 
of any other coral, being quadrangular, expanded at intervals into four 
rays, and destitute of any true tentacles. 
The different kinds of these animals grow and increase with great 
rapidity, forming enormous masses of coral, as may be judged from a 
fragment on the south side of this Room. It is their skeletons that 
form the reefs round the islands in the Pacific Ocean, the growth of 
which has furnished such an interesting problem to the scientific 
