2 
comparatively small creatures, the Almighty 
in his infinite wisdom, has effected the 'most 
extraordinary changes on the face of the globe, 
over spots where ships in ages past have doubt- 
less crossed, there are now beautiful islands, 
covered with verdure and tall trees, and teem- 
ing with human life, nor is this confined to 
narrow limits ; thousands, I might say millions, 
of these formations are to be found in narrow 
portions of the globe — all the result of the 
operations of the zoophyte. 
I find on reference to authorities on the 
subject of zoophytes, that it is to the genus 
helianthoida that we are to attribute those 
vast coral formations, which, as I have already 
remarked, are to be found in almost every 
maritime portion of the world. It is now well 
ascertained that these formations are caused by 
an excretion of calcareous matter from the 
inferior portion of the body of the zoophyte— 
a quantity of calcareous matter, the deposition 
of which, under and around the body, and in 
the tissue of the folds formed by the tunics of 
the abdominal cavity, constitutes the cell or 
polypidom into whose hollows the tenant can 
partially or wholly retire. The stony sub- 
stances so formed are called corals, and their 
mode of formation causes them exactly to re- 
present the animals which secrete them — the 
upper surface isjalways furnished with radiating 
plates, the remains of the calcareous particles 
which were deposited in the longitudinal folds 
of the stomach before referred to ; and as these 
plates do not usually reach to the centre, there 
is almost always a vacant space in the middle 
between them. The cells are either single or 
cupped, or they are branched like a tree, or 
they are aggregated together so as to form a 
resemblance to a cauliflower, or even to imitate 
the human brains — all these variations resulting 
from the manner in which the animal emits 
from the whole surface, or from a particular 
part of the sides of the body, the bud by 
which the new individual of the general mass 
or society is produced. In the absence of any 
positive theory as to the process by which the 
zoophytes form the calcareous deposits alluded 
to, I would remark that having for some years 
been employed in long sea trips in steam ships, 
after a run from Bombay to Suez and back, in 
examining the boilers, we always found a hard 
calcareous deposit of three or four inches thick 
at the bottom of the boilers, and on inspection 
this substance bore a strong resemblance to 
madrepore. I infer, therefore, that the cal- 
careous deposits made by the zoophytes may 
be caused by the action of some powerful acid, 
existing in their bodies, on the salts contained 
iu sea- water. This idea never struck me 
when I was in a position to put it to the 
test; 1 merely advance it now by way of 
suggestion to those who may have an oppor- 
tunity of enquiring into the matter. The 
helianthoida are all oviparous, the ova being 
produced in appropriate ovaries situated 
between the compartments formed by the 
septa that radiate from the outer parietes of 
the stomach to the skin. The ova are con- 
tractile and motive being carried about '♦from 
the action of the cilia that clothe the surface. 
Under the microscope they prove of diversified 
form, many resembling flattened peas, some 
elongated or exhibiting irregular prominences, 
some almost spherical, and some which cannot 
be referred to any particular figure. After 
moving about for several days, during which 
their forms suffer some slight change, they 
insensibly relax in their mQtility, the cilia 
disappear, and having become stationary, each 
ovum rapidly runs through the stages of 
development, that lead it up to the similitude 
of its parent. The productiveness of the 
species and the rapidity of their growth are 
very great. The calcareous species often form 
enormous masses of coral, of the size of which 
we cannot judge by the specimens usually 
shown in collections, which are small individuals 
taken in the sheltered places among the rocks, 
where they are not exposed to the action of the 
waves, and collected before they have 
reached their proper magnitude. The form of 
the masses appears to be greatly influenced by 
the positions in which they have grown ; and 
the size of the individual depends on the 
quantity of nourishment it is able to pro- 
cure. This is proved by the fact that if all the 
individuals of the same mass are equally 
exposed, they are of an equal size ; but if the 
surface of the coral is waved, the individuals 
on the convex part of the mass, which could 
procure the most food, are large, while those in 
the concave or sunken parts, are small. 
The productions of the coral animal in the 
warmer parts of the ocean, are not only won- 
derful in themselves on occount of their vast 
extent and the minuteness of the animals by 
which they are created, but highly interesting 
for the light they throw on the history of the 
globe. On the north-east coast of Australia, 
that is to say, on our own coast, there is a reef 
1000 miles long. The shores of the island of 
New Caledonia are fenced in by a reef 400 
miles in length. The coral islands of the 
ropical Pacific Ocean are innumerable, and 
are well known to all by the glowing descrip- 
tions of voyagers. These productions may be 
referred to three classes — Atolls, Barrier 
Reefs, and Fringing Reefs. The first 
consist of a circular wall of coral, rising 
from a considerable depth, surrounding 
a lagoon or sheet of smooth water. The wall 
is seldom entire throughout, for there are places 
through which the water can find its way from 
the ocean into the interior. The bottom of the 
confined water is usually cup-shaped, with a 
depth ranging from a few fathoms to fifty, 
whilst the outer side of the reef falls at an 
angle of about 45 to a depth of from 200 to 
300 fathoms. In violent storms large pieces of 
the wall are broken off and driven into the in- 
