College, Barbados. His mother, Annie Elizabeth, was a daughter of Captain Henry Waring, R.N., of Lyme Regis. Spending his boyhood among the hills of Cumberland and Westmoreland, he received his early education at Appleby grammar school. On leaving the latter he was sent to the university of Giittingen, where he became a student in zoology under Keferstein, and took the degree of Ph.D. Returning to Britain he studied medicine and natural science at the university of Edinburgh from 1862 till 1867 ; he took the degree of bachelor of science in 1866, and in the same year he was awarded the Baxter scholarship as the most distinguished graduate in science. In the following year (1867) he proceeded to the degrees of bachelor of medicine, master of surgery, and doctor of science ; his doctorial thesis, 'On the Geology of Cumberland,' gaining him the gold medal of the university for that year. In all the subjects of examination he gained a first class; and when, in 1869, he took the M.D. degree he was awarded the Ettles medical scholarship, as occupying the highest position among the graduates. Even in his schooldays he had devoted much attention to the geology of his native county and Westmoreland ; and while a student at Edinburgh he learnt anatomy under Goodsir, zoology under Allman, and botany under Balfour, thus laying the foundation of that wide zoological knowledge which subsequently stood him in good stead.
In 1869 he received his first appointment, that of lecturer on natural history in the extra-academical school of medicine at Edinburgh. This he held till 1871, when he visited Toronto, where he was offered and accepted the professorship of natural history in the university. This chair he retained for three years, exchanging it in 1874 for the professorship of comparative anatomy and zoology in the Royal College of Science, Dublin. No sooner, however, had he accepted the latter post than he was offered the professorship of biology in the Durham College of Physical Science. Assuming the latter appointment in preference to the former, he filled this office till 1875, when the offer of the chair of natural history at the university of St. Andrews induced him to remove to that city. Here he practically created a zoological school, and assisted in the extension of university teaching to Dundee. Nicholson remained at St. Andrews till 1882, when he was appointed regius professor of natural history in the university of Aberdeen a post which he held at the time of his death. When he first succeeded to this chair, zoology was the chief science on which he had to lecture ; but a change in the curriculum elevated geology to a more important status than previously. And it was to this branch of science that Nicholson now mainly devoted his energies ; the lectures in zoology, except for the summer course, being delivered by his assistant, Dr. Alexander Brown.
In addition to the official posts already noticed Nicholson delivered in London the annual course of Swiney lectures in geology from 1878 till 1882, and he was reappointed in 1890, continuing his lectures till 1894. During the illness of Sir Charles Wyville Thompson [q. v.], then professor of natural history at Edinburgh, Nicholson, for the greater part of the session of 1878, and the whole of those of the two following years, discharged the duties of that office. In 1880 he was appointed examiner in natural history and the cognate branches of science to the university of New Zealand.
In 1867 Nicholson was elected a fellow of the Geological Society of London, and in 1888 was awarded by the council the Lyell medal. He was also a fellow of the Linnean Society, and in 1897 was admitted to the fellowship of the Royal Society.
Nicholson died at Aberdeen on 19 Jan. 1899. As a lucid lecturer Professor Nicholson attained well-merited celebrity ; and as his bias inclined to the palæontological aspect of zoology, it was in this walk that he gained his highest reputation. His most important investigations are perhaps those connected with the palaeozoic fossils known as graptolites, which occur, although not abundantly, in the slates and shales of his native hills. Connected closely with this study was the work of unravelling the tangled skein of the geological succession of the palaeozoic rocks of the lake district; and to this task his contributions, some of which were written conjointly with Mr. J. E. Marr, are of the highest value.
Nicholson's name is, however, most widely and generally known through his zoological and palæontological text-books, which have been largely adopted, not only in the universities and colleges of the United Kingdom, but likewise in many of those of other English-speaking countries. The earliest of these is 'A Manual of Zoology for the use of Students,' the first edition of which appeared in 1870 in two volumes, and the seventh (greatly enlarged and rewritten) in one volume in 1887. The year 1872 saw the issue of the first edition of 'A Manual of Palaeontology for the use of Students,' in one volume. The second edition, which
