Sydney John Hickson, British zoologist, was awarded the degree Master of Arts (MA) by the University of Cambridge and then qualified in London as Doctor of Science (DSc) in zoology. In 1882 he started work as an assistant to H.N. Moseley*, professor of anatomy at the University of Oxford. He travelled in the Malay Archipelago during 1885-1886. In 1888 he became deputy professor of zoology at Oxford, and two years later presented lectures on advanced morphology at the University of Cambridge. By 1900 he was Beyer professor of zoology at Owen's College (Victoria University), Manchester, where he remained to his retirement.
Hickson's research in invertebrate zoology and marine biology led to a variety of publications. Several of his early papers dealt with the eyes and optic tracts of insects and molluscs (Quarterly Journal of Microscopic Science, 1880-1885) and the theory of coral reefs and atolls (Report of the British Association..., 1890). His first book, based on a visit to Indonesia, described the natural history and ethnology of the island Sulawesi: A naturalist in north Celebes (1889). This was followed by a work on the fauna of the deep sea (1893), and a more popular book, The story of life in the seas (1898).
By this time, however, Hickson had developed a more specific interest in the Alcyonaria, an order of the Class Anthozoa (Coelenterata). In 1898 and 1899 J.D.F. Gilchrist* sent him a number of dead but carefully preserved specimens of Alcyonaria from the Cape, which he described under the title "The Alcyonaria and Hydrocorallinae of the Cape of Good Hope". The paper was included in Gilchrist's Report of the Government Biologist (pp. 60-89) for 1900, and also published in Marine investigations in South Africa (1902, Vol. 1, pp. 67-96). Most of the specimens came from False Bay, Algoa Bay and near East London, and included one new genus and three new species. Part II of this paper was published in 1904 in Marine investigations in South Africa (Vol. 3, pp. 211-239).
Hickson also wrote a memoir on British Alcyonaria (1901); a chapter in a book on the Alcyonaria of the Maldives (1906); described the Alcyonaria of the Siborga expedition of 1907; and revised the family Xeniidae (Order Alcyonaria), based on the specimens collected by the Great Barrier Reef Expedition of 1928-1929, in the expedition's Scientific Reports (1931). His other work included papers on Coelenterata and Ctenophora (1906), Foraminifera of the Indian Ocean (1911), and the Gorgonacea of the Great Barrier Reef Expedition (1932); as well as a book, An introduction to the study of recent corals (1924).
Hickson was a Fellow of the Royal Society of London and served on its council from 1906 to 1908. He became a member of the British Association for the Advancement of Science in 1887 and was president of its Section D (Zoology) in 1903. By 1905 he was active in a number of the association's zoological committees, namely those dealing with "The influence of salt and other solutions on the development of the frog", "Occupation of a table at the Zoological Station at Naples" (Chairman), "The zoology of the Sandwich Islands", "Madreporaria of the Bermuda Islands" (Chairman), "Zoology organisation" (Secretary), and "Colour physiology of the higher crustacea" (Chairman). He was awarded honorary doctorates by several universities.