The Asteroidea. Report on the scientific results of the voyage of H.M.S. Challenger during the years 1873-76 under the command of Captain George S. Nares, R.N., F.R.S. and the late Captain Frank Tourle Thomson, R.N. prepared under the superintendence of the late Sir C. Wyville Thomson, Knt., F.R.S., %c. regius professor of Natural History in the University of Edinburgh director of the civilian scientific staff on board and now of John Murray one of the naturalists of the expedition