EEPOET OX THE CPJNOIDEA. 319 



bottom of red mud (PL XVI. fig. l). The cirri, though short, are very closely set, and those 

 of the five lowest whorls bend downwards underneath the last nodal joint and interlace 

 with one another so as to form a kind of basket-work just like that beneath the centro- 

 dorsal of a Comatula with many cirri, such as Anteclon eschrichti. This led Sir Wyville 

 Thomson ^ to remark that " from the attitude of the cirri and from the appearance of the 

 end of the stem there can be no doubt that this specimen is complete, that it is mature, 

 and that it was li\'ing in an unattached condition." I do not well see how this statement 

 can be disputed. Neither do I understand the difficulty of admitting that the mode of 

 life of a Pentacrinus may vary in different localities. The Comatulse are fixed when youno-, 

 and semi-free when mature, attaching themselves by their cirri to various objects ; but 

 some species [Actinometrajukesi and Actinometra stellata, &e.) eventually lose their cirri 

 altogether, and must then live an absolutely free life. The Palaeozoic Agassizocrinus and 

 Edriocrinus were attached when young, but subsequently became perfectly free. Con- 

 sidering that these great changes take place during the life of a single individual, I fail to 

 see the difficulty of admitting that a particular species of Pentacrinus can adapt itself to 

 the conditions of its existence, some young individuals fixing themselves permanently when 

 they have the opportunity ; while others living ou soft ooze in deeper water separate 

 themselves from their original anchorage and lead a partially free existence, being only 

 attached temporarily, just as a Comatula is. A precisely similar case to that oi Pentacrinus 

 wyville-thomsoni is presented by Pentacrinus deco7'us. Some individuals are firmly 

 fixed to telegraph cables by the spreading base of their stem, while others have been 

 found in the semi-free condition. 



Circumstances alter cases ; and the question of the natural freedom of the uidi\'idual 

 represented in PL XIX. fig. 1, which has five perfect cirri on a rounded nodal joint at the 

 base of the stem, is by no means negatived, because the " Talisman " found several others 

 attached by calcareous growths round the cirri of the lowest whorl. The French 

 zoologists, however, appear to consider that this observation proves Sir AVj^'Ule to have 

 been WTong ; whereas, on the contrary, the dredgings of the Challenger and the " Blake " 

 have confirmed his views in the most satisfactory manner.^ 



Except at the lowest nodal joint the cirri of Pentacrinus wyville-thomsoni appear to 

 be usually directed upwards (PL XVIII. figs. 1,3; PL XIX. fig. l) ; and the supra-nodal 

 joint is accordingly slightly grooved for the reception of the cirrus-bases (PL XIX. 

 figs, 3, 4 ; PL XXII. fig. 17) instead of the infra-nodal joint as is so markedly the case 

 in Pentacrinus hlalcei and Pentacrinus decorus (PL XXXI. figs. 1, 3 ; PI. XXXIV. fig. 1; 

 PL XXXVI.), in which the cirri are usually directed downwards. In this respect, there- 

 fore, Pentacrinus wyville-thomsoni presents an approach to the genus Metacrinus, ia 



1 The Atlantic, vol. ii. p. 126. 



^ Mucli of what has been written above would have appeared more suitably in Chapter II. pp. 18-22, where the 

 mode of life of the PentaerinidK is discussed. But as Filhol's article did not appear till after this chapter had gone to 

 the printers, and did not come under my notice till five months later, I have been obliged to take up the subject again. 



