PREFACE. 



THE Echinodermata which form the subject of this memoir were collected during the 

 voyage of H.M.SS. 'Alert' and 'Discovery,' under the command of Sir George S. Nares, 

 E.N., K.C.B., F.E.S., to the Polar Sea, by the Naturalists attached to the Expedition, 

 Capt. (now Major) H. W. Feilden and Mr. Hart. The greater number were obtained 

 from 79 20' N. lat. to 82 27' N. lat. inclusive that is, from Franklin-Pierce Bay to 

 Floeberg Beach. Some forms were captured on the outward voyage, in 65 N. lat.; 

 and others were dredged in the Expedition of H.M.S. ' Valorous,' between 66 56' 

 and 70 30' N. lat., by Dr. J. Gwyn Jeffreys. F.R.S. One specimen was taken by 

 Mr. A. C. Horner (who accompanied Sir Allen Young in the 'Pandora'), in Smith's 

 Sound, 78 19' N. lat. The Arctic Circle has been regarded as our southern limit. 



The collections were made under great difficulties, and especially those from the 

 highest latitudes : dredging, when the tangles froze on coming out of the sea, could not 

 be attempted frequently. Nevertheless the specimens collected were numerous. They 

 were carefully cleaned ; and some were preserved in spirit, and others were permitted 

 to dry. 



After being deposited at the Royal Society in 1877, the collection was forwarded 

 to the British Museum. Dr. Giinther, F.R.S., confided the specimens to the authors 

 of this Memoir ; and we wrote a brief description of them in the ' Annals & Magazine 

 of Natural History,' 1877, vol. xx. pp. 449-470. Subsequently we contributed a 

 short notice of these interesting objects to the admirable book written by Sir George 



