Of the Royal Society Sir William was elected a Fellow in 1864—at the relatively early age of thirty-three—and he served on the Council of that body for three separate periods, namely from 1868 to 1870, from 1876 to 1878, and again from 1884 to 1886, while in 1884 and 1885 he was one of the Vice-Presidents. In 1882 his conspicuous services to zoological science was recognised by the bestowal upon him of a Royal Gold Medal—one of the most honourable distinctions in the gift of the Society; the other recipient in the same year of a similar honour being Lord Rayleigh. In handing to Professor Flower this medal, the President dwelt upon the value of his contributions to both zoology and anthropology, referring, in connection with the former science, to his paper on the classification of the Carnivora, and, in respect to the latter, to the then recently published first part of the “Catalogue of Osteological Specimens in the Museum of the Royal College of Surgeons,” in which descriptions and measurements of between 1300 and 1400 human skulls are recorded. The present writer has been informed that Flower refused to be nominated for the Presidentship of the Royal Society, owing to the fear that the calls made upon his time by that office would interfere with his official duties. Of the Zoological Society Professor Flower became a Fellow so long ago as the year 1851, that is to say, three years previous to the commencement of his Crimean service. After serving for several periods on the Council he was elected to the honourable (and honorary) office of President on the death of the Marquis of Tweeddale in 1879, and in this important position he remained till his death. It should be added that Flower never received one of the medals of the Zoological Society, and this for the very good reason that such rewards are bestowed in recognition of gifts to the Society’s Menagerie, and not for contributions to zoological knowledge. Flower’s contributions to both the _Transactions_ and the _Proceedings_ of the Society were numerous, and, needless to say, valuable; the earliest in the former having been published in 1866, and in the latter in 1852. With very few exceptions, these communications relate to mammals. Fuller details with regard to Sir William’s Presidency of the Zoological Society will be found in a later chapter. Of the Linnean Society, Flower was elected a Fellow in 1862, but he does not appear to have ever taken any active part in the administration of that body, or to have contributed to its publications, although for a time he was a Vice-President.