694 THE POPULAR SCIENCE MONTHLY. 



and some speculations on the development of certain medusoid forms, 

 which attracted notice and were considered too daring by Johnston 

 and Edward Forbes. During this period, too, he entered upon those 

 researches of the crinoids of past times and the crinoidal forms of 

 modern times, of which he took Comatula rosacea as a typical speci- 

 men, which, with their direct and indirect results, led him up to the 

 grand work of his life. A British pentacrinus had been discovered and 

 described by Vaughn Thompson thirty years before, and determined 

 by him to be but the young stage of the " rosy feather-star," but noth- 

 ing more bad been learned about it. Professor Thomson undertook to 

 complete the investigation and fill out the life-history of the animal ; 

 and the account of his researches was given to the Royal Society in 

 1862 and published in the volume of the " Philosophical Transactions " 

 for 1865. This investigation on the pentacrinoid stages of comatula 

 was but a part of a series of observations on the genus Pentacrinus 

 itself, and Professor Thomson collected a mass of material with the 

 object of writing a memoir on the group. 



Up to nearly this time, it had not been believed by scientific men 

 that life did or could exist below a certain depth of the sea. Professor 

 Forbes had admitted the existence of a zone of deep-sea coral extend- 

 ing from fifty fathoms below the surface to an unknown depth, a 

 region in which, he held, " as we descend deeper and deeper, its inhabit- 

 ants become more and more modified and fewer and fewer, indicating 

 our approach toward an abyss where life is either extinguished or ex- 

 hibits but a few sparks to mark its lingering presence." This skepti- 

 cism, however, was becoming weaker under the testimony of living 

 specimens that were from time to time brought up from undoubtedly 

 great depths. 



About 1864, Mr. G. O. Sars, of the Norway Fisheries Commission, 

 dredged up a number of specimens of a strange crinoid from a depth 

 of seven hundred feet, and, continuing to dredge, found an abundance 

 of animal life at about the same depth. Professor Thomson was in- 

 vited by Sars's father, the illustrious Professor Michael Sars, to visit 

 Christiania and see the specimens. The two, after examining them, 

 concluded that they were closely related to one of the fossil genera, 

 allied to the family of the Apiocrinidce. Here, then, they had a living 

 representative of a group supposed to be extinct, and of a form which 

 had lived over from the Cretaceous epoch. 



In 1868 Dr. Carpenter, being engaged in investigations on a living 

 crinoid from the West Indies, visited Professor Thomson to discuss 

 the subject in which they were both interested ; and on this occasion 

 Thomson told his visitor that the one unexplored field awaiting the 

 investigation of naturalists was the sea ; that he was convinced that 

 when explored it would yield immense treasures to science ; and sug- 

 gested to him to use his influence with the Admiralty to secure the 

 grant of a vessel, suitably fitted up for deep-sea research. The use of 



