# Dictionary of National Biography, 1885-1900/Jeffreys, John Gwyn

​JEFFREYS, JOHN GWYN (1809–1885), conchologist, was born at Swansea on 18 Jan. 1809. He was the eldest of four children, and was educated at Swansea grammar school, where he became ‘head boy,’ and from whose master, Mr. Griffiths, he received his first lessons in shell collecting. At the age of seventeen Jeffreys was articled to a local solicitor. After a successful career of many years in his profession at Swansea, Jeffreys was called to the bar in 1856, when he removed to London, his object being to ​practise in the court of chancery and before parliamentary committees. Retiring from practice in 1866, Jeffreys purchased Ware Priory in Hertfordshire, a fine old house, which became a meeting-place for many British and foreign naturalists. He was J.P. for the counties of Glamorgan, Brecon, and Herts, D.L. for Hertfordshire, and high sheriff of the last named county in 1877. He was elected a fellow of the Linnean Society in 1829, and a fellow of the Royal Society in 1840. The university of St. Andrews bestowed upon him the honorary degree of LL.D. He did much work in connection with the British Association, of which body he was local treasurer at the Swansea meeting of 1848, vice-president in 1880, and president of the biological section in 1877. For many years he acted as treasurer of the Linnean and Geological societies, and of the Royal Society Club. After the death of his wife, Jeffreys removed to Kensington, where he died suddenly of apoplexy on 24 Jan. 1885. He married a daughter of R. J. Nevill, esq., of Llangennech Park, Carmarthenshire, who died in 1881, leaving six children.
Jeffreys had a keen eye for minute distinctions, with an excellent memory, and the methodical habits of a good man of business. He wrote more than one hundred papers on scientific subjects, the first of which, ‘A Synopsis of the Pneumonobranchous Mollusca of Great Britain,’ appeared in the Linnean Society's ‘Transactions’ for 1828. Of his many other communications to scientific periodicals, perhaps the most important is his series of papers in the ‘Proceedings of the Zoological Society,’ 1868–70, on ‘The Mollusca of the Lightning and Porcupine Expeditions, 1868–70.’ But Jeffreys' chief work was his ‘British Conchology,’ 5 vols. 1862–1869, in which all the generic types of our shells are illustrated.
Jeffreys was led to undertake deep-sea dredging by his belief that the molluscs of the present day are the direct descendants of those which inhabited British seas during the period of the Crag. While engaged in his profession Jeffreys' time for collecting specimens was very limited; but he managed to pay a visit to the Shetlands for this purpose as early as 1841. Afterwards he joined Mr. Barlee, one of the old school of conchologists, sharing the expenses and the specimens obtained, while Barlee did the collecting. After Barlee's death Jeffreys was enabled to devote himself more fully to scientific work, and, in company with Mr. Waller and the Rev. A. M. Norman, the summers of most of the years between 1860 and 1870 were spent in dredging the shallower parts of the British seas in search of shells, &c., the work being done from the yacht Osprey. So important were the results obtained by these and other investigations, that in 1869 her majesty's ship Porcupine was detailed for deep-sea explorations; and with Jeffreys in charge of the scientific work, she dredged down to 1,476 fathoms off the west coast of Ireland (see Report in Proc. Royal Society, vol. xviii., 1869). In 1870 Jeffreys went in the Porcupine to dredge the deep sea in the Bay of Biscay and off the Portuguese coast. Here one haul brought up from a depth of 994 fathoms 186 species of shells, of which Jeffreys found 71 to be new to science; while of the others, 24 species had previously only been known as fossils. Another prize of this expedition was the wonderful crinoid, Pentacrinus Wyville-Thomsoni. In 1876 Jeffreys did more dredging on board her majesty's ship Valorous in Baffin's Bay, &c. In 1878 and 1879 he conducted similar work, in conjunction with Dr. Norman, off the Norwegian coast, and in 1880 the two naturalists, on the invitation of the French government, took part in the expedition on board Le Travailleur for dredging at great depths off the Bay of Biscay. In much of his deep-sea work Jeffreys was associated with Dr. W. B. Carpenter and Professor Wyville-Thomson.
Jeffreys's magnificent collection of European mollusca, which abounded in type specimens, was purchased two years before his death by the American government.
[Proceedings, Royal Society, 1885, pp. i–xv; Nature, 1885, xxxi. 317; Royal Society's Cat. of Scientific Papers, 1865–78.]
W. J. H.