WYVILLE THOMSON 41 



" Challenger." We can also trace the steps in his Echino- 

 derm studies which seem to have led him to the fruitful field 

 of deep-sea exploration. Palseontological investigation sug- 

 gested work on living Crinoids, and the news that a strange 

 new stalked Crinoid (Rhizocrinus), related to the fossil 

 Apiocrinidae, had been found living in Northern seas, induced 

 him, in 1866, to visit Professor Michael Sars at Christiania, 

 and examine for himself the remarkable collection of rare 

 animals that his son, George Ossian Sars, had brought up 

 from deep water (over 300 fathoms) in the Lofoten fjords. 

 He was struck by their novelty and deep interest and by 

 their resemblance to and bearing upon some of the extinct 

 animals of former geological periods, and especially of the 

 Chalk. 



Thus inspired, he urged his friend, Dr. W. B. Carpenter, 

 with whom he was then w^orking at the later development of 

 Antedon, to join him in endeavouring to promote an expedi- 

 tion to explore the deep waters of the Atlantic along the north- 

 west coasts of Europe. Dr. Carpenter's powerful advocacy 

 induced the Council of the Ro^^al Society to use its influence 

 with the Hydrographer, with such success that the Admiralty 

 consented to place first one and then another small surveying 

 steamer at the disposal of a committee of scientific experts 

 for expeditions under the leadership of the two enthusiasts. 

 After the first summer, a third naturalist of European fame. 

 Dr. Gwyn Jeffreys, author of the five volumes on British 

 Conchology, joined Carpenter and Thomson in conducting 

 the practical work at sea ; and the account of how, in 1868, 

 H.M.S. " Lightning," and, in 1869 and 1870, H.M.S. " Por- 

 cupine," were equipped by the Admiralty and sent out to 

 explore the depths, from the Faroes in the North to Gibraltar 

 and beyond in the South, is given in full detail in Wyville 

 Thomson's great work, The Depths of the Sea, which may be 

 regarded as the first general textbook of oceanography. 

 It was published just as the " Challenger " expedition was 

 leaving England, and so gives us a statement of matters and 



