iv THE VOYAGE OF H.M.S. CHALLENGER. 



kindly permitted me to make use of them here. They are distinguished by the initials 

 " W. B. C"; while thirty-one of the remaining thirty-six which are marked " P. H. C," 

 have been drawn under my own superintendence by Messrs. C. Berjeau, F.L.S., and 

 P. Highley. I am very greatly indebted to both these gentlemen for the care and skill 

 with which they have performed a difficult and laborious task, one, moreover, involving 

 a considerable acquaintance with minute structural details. I am under similar obliga- 

 tions to Mr. George West, who lithographed three anatomical plates, and also gave me 

 valuable information respecting the specimens from which he had drawn several plates 

 for Sir Wyville Thomson. I have likewise to thank Mr. Black for similar information 

 concerning those plates which had been drawn by himself; and also Mr. W. E. Hoyle, M.A., 

 of the Challenger Office, for kindly working out the magnification of some of the figures 

 ujaon Mr. Black's plates. 



I have further gratefully to acknowledge much valuable bibliographical assistance from 

 my friends Prof F. J. Bell, F.Z.S., and Mr. W. P. Sladen, F.L.S.; while my thanks 

 are also due to Prof. H. N. Moseley, Dr. P. P. C. Hoek, Mr. H. B. and Dr. G. S. Brady, 

 and to Mr. Edgar Smith, F.Z.S., for kindly identifying various organisms which I had 

 found attached to difi'erent parts of the Crinoids. 



Prof. Carl Zittel of Munich and Prof. G. Meneghiui of Pisa have been good enough to 

 send me several fossil specimens oi Rhizocrinns for examination, and I take this opportunity 

 of thanking them. But I find it difficult to express my indebtedness to Mr. Charles 

 Wachsmuth of Burlington, Iowa, U.S., who is so well known as the leading authority 

 upon the Palseocrinoidea. Not only has he frequently sent me for examination very rare 

 and valuable specimens illustrating the morphology of the Pateocrinoids and Blastoids, 

 but he has repeatedly answered my inc[uiries in the fullest and most complete manner 

 possible. The relations of the Neocrinoids and the Palseocrinoids have been the subject 

 of a prolonged discussion between us, extending over more than two years ; and it is a 

 matter of sincere regret to me that we have been obliged to agree to differ. Time will 

 show how far our respective views will need modification. We have approached the 

 subject from different sides ; but upon one point we are in comjilete accordance, viz., the 

 desire to find out the truth, whether or not it agree with our own ideas upon the 

 subject. Mr. Wachsmuth will shortly ^lublish an explanation of his own position, to 

 which I would refer those who are interested in the matter. 



In conclusion, I must express my sincere thanks to Mr. John Murray and to 

 Prof. Alexander Agassiz for having entrusted me with the working out of the Crinoid 

 collections in their charge, and for their readiness to afford me every possible assistance 

 in doing so ; while I would pay a heavy debt of gratitude to the memory of the late Sir 

 Wyville Thomson. It was my privilege to accompany him and my father in the short 

 but eventful cruise of H.M.S. " Lightning " in the year 1868 and in the "Porcupine" 

 expedition of 1869; and to his kindness and encouragement both then and sub- 



