Zoologist, born at Bonsyde, Linlithgow; educated at Merchiston Castle, Edinburgh, and at the university there; a lecturer on botany at Aberdeen, professor of Natural History in Queen's College, Cork, of Geology at Belfast, and of Natural History in the University of Edinburgh; accompanied the Challenger expedition (1872-1876) as head of the scientific department; knighted 1876; wrote "The Depths of the Sea" and "The Voyage of the Challenger " (1830-1882).