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



the same character "as occurring in some specimens of Pentacnnus mulleri" i.e., the 

 type now known as Pentacrinus decorus. 



Filhol continues, however, " nous avons constate, apres avoir remonte des debris de 

 roches, que ces animaux vivaient, contrairement h ce que Ton avait cru pouvoir supposer, 

 completement fixds par des cirres recourbes se detachant de I'articuLation terminale de la 

 tige. Ces sortes de crochets se soudent en quelque sorte avec le fond sur lequel ils 

 reposent et il faut les briser pour les detacher. Par consequent les Pentacrinus Wyville- 

 Thompsoni {sic), que Ton a recontres libres, avaient d<\ etre arraches a la suite de quelque 

 accident du fond sur lequel ils vivaient, car il parait l^ien difficile d'admettre que les 

 niemes animaux en des points divers de I'ocean aient des modes d'esistence differents." 



The observations here recorded are undoubtedly of great value ; but the conclusions 

 drawn from them by Filhol appear to me to be somewhat rash. The " Talisman" speci- 

 mens of Pentacrinus wyville'thomsoni seem to have been living on a stony or rocky 

 bottom ; and in fact Prof. Perrier ^ records that " plusieurs ont ete ramenees avec les 

 cailloux sur lesquels Us sont fixes." There can be no question therefore that Pentacrinus 

 wyville-thomsoni lives in a permanently fixed condition on a hard bottom. But the 

 "accident" which is supposed by Filhol to have liberated some fifteen fixed individuals 

 must have been of a rather extensive character ; and it must further have taken place at 

 a sufficiently long time l:)efore they were dredged by the " Porcupine " for the lowest nodal 

 joint of one of them to have lost its natural appearance (PI. XXII. fig. 20) and have 

 become enlarged and rounded as shown on PI. XXII. fig. 27. But in other specimens the 

 lowest nodal joint is far less modified. It retains its pentagonal shape and the thickened 

 rim of the syzygial face, in the centre of which there is a small rounded tubercle covering 

 the opening of the central canal. If aU these specimens had been detached by one 

 general " accident " anterior to the arrival of the " Porcupine's " dredge and tangles 

 among them, their lowest nodal joints should have been in the same condition and not 

 in difi"erent stages of modification. The same " accident " must have happened to the 

 Pentacrinus decorus of the Caribbean Sea and to the Pentacrinus maclearanus of the 

 Challenger dredgings, lioth of which w^ere described by Sir Wyville as having the stems 

 closed up at a modified nodal joint ; but Filhol makes no reference whatever to these two 

 types. He does not appear to dispute the fact that the " Porcupine " individuals of 

 Pentacrinus wyville-thomsoni were free when captured ; but he regards the observations 

 of the "Talisman" as proving that this condition was not a natural one. Sir Wyville^ 

 believed that although the Pentacrinus, like the young Comatula, " was doubtless attached 

 in its early days, it appears to have finally parted from its attachment, and to have led a 

 free life ; " and he pointed out that the syzygial union of the stem-joints at the nodes 

 facilitated the rupture of the stem, just as is the case with the syzygies in the arms. His 



' L'Expedition du Talisman, Revue Scientifique, No. 24, December 15, 1883, p. 741. 

 ^ Sea Lilies, The Intellectual Observer, August 1864, p. 7. 



