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MR. DARWIN,

I have much pleasure in announcing that a Royal Medal has been awarded to you.

Adopting the views of Sir Charles Lyell, who has sought to explain natural phenomena by an appeal to the evidence afforded by still active causes, you have observed with great care, and no one has been more judicious, or more successful, in collecting facts. The frequent references made to your labours by writers on general geology, are evidence of the estimation in which they are held. Your work on Coral Reefs is a fine specimen of an able argument on facts. In that work you have brought together all the information collected by others, as well as by yourself, and you have explained the facts observed relating to the distribution of coral reefs, the conditions favourable to their increase, the rate of their growth, and the depth at which they are found; and thus laying a sound foundation to reason upon, you have shown that, with few exceptions, the old theory, that these reefs have been formed on the edges of submarine craters, and generally that the rocky or other basis on which the corals have grown had been elevated, is incorrect; and, on the contrary, that the true theory is, that the surface has been gradually brought down to the proper level, a depth for the growth of corals, by gradual subsidence. No one probably can read your book without assenting to the general truth of your reasoning; and as it places the fact of subsidence beyond doubt, a fact more difficult to prove than elevation, and exhibits it on a scale of magnitude and generalization quite commensurate with that of elevation, I think it must be accepted as one of the most important contributions to modern geology.

In your Monograph on the Pedunculated Cirripeds, you have treated generally of the structure, economy, and zoological relations of these animals, and given a systematic arrangement and description of the different species. In the accomplishment of your task, you have not only made use of previously existing materials with sound and enlightened criticism, but, by the discovery of new facts and the promulgation of original views, contributed most materially to advance the department of knowledge to which your researches more immediately belong, and rendered valuable service to physiological science in general.

In the course of your inquiries you have confirmed and widely extended the observations of your predecessors respecting the larval condition of the Cirripeds, and have shown that all the perfect Lepads and Balanids pass through successive stages of metamorphosis. You have also added largely to our knowledge of the anatomy of the larva, and brought to light the curious fact, that in one of its stages its mouth is altogether rudimentary, and perfectly closed up by the external covering, so that the creature in this stage is in fact a "locomotive pupa," incapable of feeding. You have further observed that the prehensile antennae with which the larva fixes itself in its final change, invariably remain permanent in the adult animal

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at the attached end of its peduncle, and in many cases afford important characters for zoological discrimination.

The knowledge thus gained from the study of development is most sagaciously and happily applied by you to explain the homological relations between the Cirripeds and Crustaceans; and in this way you have conclusively shown that the peduncle of the mature Lepad corresponds with the three anterior segments of the Crustacean. Again, by your discovery of Proleolepas, a new parasitic Cirriped of low organization, you have been able successfully to compare the remaining segments of the body in the two classes; for whilst the chain of evidence is in some measure broken by the absence of two segments near the middle of the series in Cirripeds generally, the missing links are supplied by the newly-discovered animal referred to.

The existence of an eye with a pair of ophthalmic ganglia in adult Lepads, as had been previously shown in Balanids,—the presence too of organs seemingly intended for hearing and smelling—the chemical nature of the tegumentary coverings—the cement-gland and ducts, yielding a plastic material for attaching the peduncle and for other special purposes in particular instances, and the singular organic connexion between that gland and the ovaries, are all most interesting discoveries in comparative anatomy, first made known in your work.

Some very singular facts respecting the reproductive function in the Lepadida? have been brought to light through your researches. You observed that the ova, on leaving the ovary, are gathered in a layer underneath the internal lining of the sac or mantle, from whence they are freed and extruded by the process of moulting, and then form the ovigerous lamella? already known. Again, you have clearly established, that, contrary to the hitherto received opinion, there are species of Lepadidae consisting of individuals of distinct sexes, the male being parasitic on the female; and in certain other species you have discovered a condition hitherto unknown in the animal kingdom, —namely, bisexual individuals impregnated by parasites simply of the male sex, which you name "complemental males,"—a fact unquestionably of first-rate interest in relation to the physiology of the reproductive function in general.

Besides these more important observations, there are many more of lesser mark to be met with in the descriptions of particular species,—descriptions, it may be observed, which are founded on a careful examination, not only of the external characters, but of the internal structure of the animals in question, in specimens obtained from every available source, both at home and abroad; and the zoological distinctions are rendered more precise and intelligible than heretofore, by the introduction of a consistent and philosophical nomenclature.