FOUR np:w species of the crinoid (;enus 



RHIZOCRINUS. 



By Austin Hobart Clark, 



CoUaborator, Dirisioii, of Marine Invertebrates, U. S. National Museum. 



In his report upon the stalked crinoids collected by the Challenge?', 

 Dr. P. H. Carpenter admitted only two recent species of the genus 

 Rhisocrinus, R. lofote.nKis, and R. rawsoni The former is credited 

 with a geographical range extending from the Lofoten Islands and 

 Nantucket (Mass.) southward to Uruguay, and with a bathymetric 

 range of from 80 to 1,900 fathoms; the latter is said to inhabit the 

 Atlantic coasts of southern Europe and northern Africa, and to 

 occur among the outlying groups of islands and throughout the 

 West Indies at depths of from 73 to 1,277 fathoms. The first record 

 of lofotensis is, of course, the original description of Sars, in 18G4, 

 when the genus was founded; the first record of rawsoni (under the 

 name lofoterDiis) is that published in 1870 by Fischer,* who had 

 obtained specimens off Setuval, Portugal, this antedating by two 

 years Sir Wyville Thomson's record of the Porcupine specimens, cited 

 as the first by Carpenter. 



In 1883 Professor Perrier had described a supposedly new crinoid 

 which had been dredged by the Travailleur off Morocco under the 

 name of Dernocrinus jyarfaiti. This new genus was strongly criticised 

 by Carpenter, who placed the t3^pe-species under the synonymy of 

 Rhizocrinus rawsoni, as understood by him. Two years later (a year 

 after the publication of the Challenger report) Perrier described, 

 under the nanie of llyoerinus recuperatus, a very remarkable species, 

 in all essentials a Bathycrinns, but having separate basals. This was 

 also subjected to severe criticism by Carpenter. In the next year 

 Korotneff' reported the discovery of a large species of ^''Rliyzocrhius " 

 in the Straits of Sunda,. where it was easily obtainable before the 

 eruption of Krakatoa.^ 



Aside from a few additional records by Rathbun, Koehler, Chun, 

 Grieg, and Agassiz (the last proving to be a Bathycrinus), nothing 



"Actes de la Soc. linn, de Bordeaux, XXVII, p. 351. 

 ^'Bull. de I'acad. roy. de Belgique [3], XII, p. 55S. 



Proceedings U.S. National Museum, Vol. XXXVI— No. 1693. 



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