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ondences of thought, those intellectual links in Creation, which give such coherence and consistency to the whole, and make it intelligible to man.
The lowest in structure among the Polyps are not Corals, but the single, soft-bodied Actiniae. They have no solid parts, and are independent in their mode of existence, never forming communities, like the higher members of the class. It might at first seem strange that independence, 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,