Quarterly Journal of Microscopical Science and to the Transactions of the Royal and Linnaean Societies he contributed a large number of memoirs dealing with the microscopic anatomy and relationships of invertebrates, and, lastly, he gave a series of addresses at the Royal Institution, which had been founded as a means by which leading men of science might give accounts of their work to London society.  Abstracts of these lectures are published in the early volumes of the Proceedings of the Royal Institution and are interesting as shewing the kinds of zooelogical subjects which were attracting the attention of Huxley and which he considered of sufficient interest and importance to bring to the notice of the general public.  The first of these lectures, and probably the first given in public by Huxley, occurred on April 30, 1852, and was entitled “Animal Individuality.”  The problem as to what is meant by an individual had been raised in his mind by consideration of many of the forms of marine life, notably compound structures like the Portuguese man-of-war, and creatures like the salps, which form floating chains often many yards in length.  He explained that the word individual covers at least three quite different kinds of conceptions.  There is, first, what he described as arbitrary individuality, an individuality which is given by the mind of the observer and does not actually exist in the thing considered.  Thus a landscape is in a sense an individual thing, but only so far as it is a particular part of the surface of the earth, isolated for the time in the mind of the person looking at it.  If the observer shift his position, the range of the landscape alters and becomes something else.  Next there are material, or practically accidental individual things, such as crystals or pieces of stone; and, lastly, there are living individuals which, as he pointed out, were cycles.  All living things are born into the world, grow up, and die, and it was to the cycle of life, from the egg to the adult which produces eggs, that he gave the name individual.  In a simple animal like Hydra there is no difficulty in accepting this plain definition of individuality; but Huxley went on to compare with Hydra a compound creature like the Portuguese man-of-war, which really is composed of a colony of Hydra-like creatures, the different members of the colony being more or less altered to serve different functions.  All these have come from the branching of a single simple creature produced from an egg, and to the whole colony Huxley gave the name of zooelogical individual.  The salps give a still wider interpretation to this view of individuality.  The original salp produced from the egg gives rise to many salps, which may either remain attached in a chain, or, breaking away from one another, may live separately.  Huxley extended the use of the word individual so as to include as a single zooelogical individual the whole set of creatures cohering in chains or breaking apart, which