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the Royal Society of London； which never had； and it is to be hoped
never will have； anything of an academic constitution； and finally
he took himself off to Guadaloupe； and became lost to science
altogether。
Fifteen or sixteen years after the date of Peyssonel's suppressed
paper； the Abbe Trembley ＇118＇ published his wonderful researches upon
the fresh…water Hydra。 Bernard de Jussieu ＇119＇ and Guettard ＇120＇
followed them up by like inquiries upon the marine sea…anemones and
corallines； Reaumur； convinced against his will of the entire justice
of Peyssonel's views； adopted them； and made him a half…and…half
apology in the preface to the next published volume of the
〃Memoires pour servir l'Histoire des Insectes；〃 and； from this time
forth； Peyssonel's doctrine that corals are the work of animal
organisms has been part of the body of established scientific
truth。
Peyssonel； in the extract from his memoir already cited； compares
the flower…like animal of the coral to a 〃poulpe；〃 which is the
French form of the name 〃polypus；〃〃the many…footed；〃which the
ancient naturalists gave to the soft…bodied cuttlefishes； which；
like the coral animal； have eight arms； or tentacles； disposed
around a central mouth。 Reaumur； admitting the analogy indicated
by Peyssonel； gave the name of polypes； not only to the sea…
anemone； the coral animal； and the fresh…water Hydra； but to what
are now known as the Polyzoa； and he termed the skeleton which they
fabricate a 〃polypier；〃 or 〃polypidom。〃
The progress of discovery； since Reaumur's time； has made us very
completely acquainted with the structure and habits of all these
polypes。 We know that； among the sea…anemones and coral…forming
animals； each poylpe has a mouth leading to a stomach； which is
open at its inner end； and thus communicates freely with the
general cavity of the body； that the tentacles placed round the
mouth are hollow； and that they perform the part of arms in seizing
and capturing prey。 It is known that many of these creatures are
capable of being multiplied by artificial division； the divided
halves growing； after a time； into complete and separate animals；
and that many are able to perform a very similar process naturally；
in such a manner that one polype may； by repeated incomplete
divisions； give rise to a sort of sheet； or turf； formed by
innumerable connected； and yet independent； descendants。 Or； what
is still more common； a polype may throw out buds； which are
converted into polypes； or branches bearing polypes； until a tree…
like mass； sometimes of very considerable size； is formed。
This is what happens in the case of the red coral of commerce。 A
minute polype； fixed to the rocky bottom of the deep sea； grows up
into a branched trunk。 The end of every branch and twig is
terminated by a polype； and all the polypes are connected together
by a fleshy substance； traversed by innumerable canals which place
each polype in communication with every other； and carry
nourishment to the substance of the supporting stem。 It is a sort
of natural cooperative store； every polype helping the whole； at
the same time as it helps itself。 The interior of the stem； like
that of the branches； is solidified by the deposition of carbonate
of lime in its tissue； somewhat in the same fashion as our own
bones are formed of animal matter impregnated with lime salts； and
it is this dense skeleton （usually turned red by a peculiar
colouring matter） cleared of the soft animal investment； as the
hard wood of a tree might be stripped of its bark； which is the red
coral。
In the case of the red coral； the hard skeleton belongs to the
interior of the stem and branches only； but in the commoner white
corals； each polype has a complete skeleton of its own。 These
polypes are sometimes solitary； in which case the whole skeleton is
represented by a single cup； with partitions radiating from its
centre to its circumference。 When the polypes formed by budding or
division remain associated； the polypidom is sometimes made up of
nothing but an aggregation of these cups； while at other times the
cups are at once separated and held together； by an intermediate
substance； which represents the branches of the red coral。 The red
coral polype again is a comparatively rare animal； inhabiting a
limited area； the skeleton of which has but a very insignificant
mass； while the white corals are very common； occur in almost all
seas； and form skeletons which are sometimes extremely massive。
With a very few exceptions； both the red and the white coral
polypes are； in their adult state； firmly adherent to the sea…
bottom； nor do their buds naturally become detached and locomotive。
But； in addition to budding and division； these creatures possess
the more ordinary methods of multiplication； and； at particular
seasons； they give rise to numerous eggs of minute size。 Within
these eggs the young are formed； and they leave the egg in a
condition which has no sort of resemblance to the perfect animal。
It is； in fact； a minute oval body； many hundred times smaller than
the full grown creature； and it swims about with great activity by
the help of multitudes of little hair…like filaments； called cilia；
with which its body is covered。 These cilia all lash the water in
one direction； and so drive the little body along as if it were
propelled by thousands of extremely minute paddles。 After enjoying
its freedom for a longer or shorter time； and being carried either
by the force of its own cilia； or by currents which bear it along；
the embryo coral settles down to the bottom； loses its cilia； and
becomes fixed to the rock； gradually assuming the polype form and
growing up to the size of its parent。 As the infant polypes of the
coral may retain this free and active condition for many hours； or
even days； and as a tidal or other current in the sea may easily
flow at the speed of two or even more miles in an hour； it is clear
that the embryo must often be transported to very considerable
distances from the parent。 And it is easily understood how a
single polype； which may give rise to hundreds； or perhaps
thousands； of embryos； may； by this process of partly active and
partly passive migration； cover an immense surface with its
offspring。
The masses of coral which may be formed by the assemblages of
polypes which spring by budding； or by dividing； from a single
polype； occasionally attain very considerable dimensions。 Such
skeletons are sometimes great plates； many feet long and several
feet in thickness； or they may form huge half globes； like the
brainstone corals； or may reach the magnitude of stout shrubs or
even small trees。 There is reason to believe that such masses as
these take a long time to form； and hence that the age a polype
tree； or polype turf； may attain； may be considerable。 But； sooner
or later； the coral polypes； like all other things； die； the soft
flesh decays； while the skeleton is left as a stony mass at the
bottom of the sea； where it retains its integrity for a longer or a
shorter time； according as its position affords more or less
protection from the wear and tear of the waves。
The polypes which give rise to the white coral are found； as has
been said； in the seas of all parts of the world； but in the
temperate and cold oceans they are scattered and comparatively
small in size； so that the skeletons of those which die do not
accumulate in any considerable quantity。 But it is otherwise in
the greater part of the ocean which lies in the warmer parts of the
world； comprised within a distance of about eighteen hundred miles
on each side of the equator。 Within the zone thus bounded； by far
the greater part of the ocean is inhabited by coral polypes； which
not only form very strong and large skeletons； but associate
together into great masses； like the thickets and the meadow turf；
or； better still； the accumulations of peat； to which plants give
rise on dry land。 These masses of stony matter； heaped up beneath
the waters of the ocean； become as dangerous to mariners as so much
ordinary rock； and to these； as to the common rock ridges； the
seaman gives the name of 〃reefs。〃
Such coral reefs cover many thousand square miles in the Pacific
and in the Indian Oceans。 There is one reef； or rather great
series of reefs； called the Barrier Reef； which stretches； almost
continuously； for more than eleven hundred miles off the east coast
of Australia。 Multitudes of the islands in the Pacific are either
reefs themselves； or are surrounded by reefs。 The Red Sea is in
many parts almost a maze of such reefs； and they abound no less in
the West Indies； along the coast of Florida； and even as far north
as the Bahama Islands。 But it is a very remarkable circumstance
that； within the area of what we may call the 〃coral zone；〃 there
are no coral reefs upon the west coast of Ameri