ndependence,
considered a sign of superiority in the higher animals, should here be
looked upon as a mark of inferiority. But independence may mean either
simple isolation, or independence of action; and the life of a single
Polyp is no more independent in the sense of action than that of a
community of Polyps. It is simply not connected with or related to the
life of any others. The mode of development of these animals tells us
something of the relative inferiority and superiority of the single ones
and of those that grow in communities. When the little Polyp Coral, the
Astraean or Madrepore, for instance, is born from the egg, it is as free
as the Actinia, which remains free all its life. It is only at a later
period, as its development goes on, that it becomes solidly attached to
the ground, and begins its compound life by putting forth new beings
like itself as buds from its side. Since we cannot suppose that the
normal development of any being can have a retrograde action, we are
justified in believing that the loss of freedom is in fact a stage of
progress in these lower animals, and their more intimate dependence on
each other a sign of maturity.

There are, however, structural features by which the relative
superiority of these animals may be determined. In proportion as the
number of their parts is limited and permanent, their structure is more
complicated; and the indefinite multiplication of identical parts is
connected with inferiority of structure. Now in these lowest Polyps, the
Actiniae, the tentacles increase with age indefinitely, never ceasing to
grow while life lasts, new chambers being constantly added to correspond
with them, till it becomes impossible to count their numbers. Next to
these come the true Fungidae. They are also single, and though they are
stony Corals, they have no share in the formation of Reefs. In these,
also, the tentacles multiply throughout life, though they are usually
not so numerous as in the Actiniae. But a new feature is added to the
complication of their structure, as compared with Actiniae, in the
transverse beams which connect their vertical partitions, though they do
not stretch across the animal so as to form perfect floors, as in some
of the higher Polyps. These transverse beams or floors must not be
confounded with the horizontal floors alluded to in a former article
as characteristic of the ancient Acalephian Corals, the Rugosa and
Tabulata. For in the latter these