REPORT ON THE CRINOIDEA. 319 
bottom of red mud (Pl. XVI. fig. 1). 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 Antedon 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 living 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 Comatule are fixed when young, 
and semi-free when mature, attaching themselves by their cirri to various objects; but 
some species (Actinometra jukesi and Actinometra stellata, &c.) eventually lose their cirri 
altogether, and must then live an absolutely free life. The Paleozoic 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 ethers living on soft ooze in deeper water separate 
themselves from their original anchorage and lead a partially free existence, being only 
attached temporarily, just as a Comatulais. A precisely similar case to that of Pentacrinus 
wyville-thomsont is presented by Pentacrinus decorus. 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 individual 
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 Wyville to have 
been wrong; 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-thonsoni appear to 
be usually directed upwards (Pl. XVUL. figs. 1,3; PL XIX. fig. 1); 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 blakei and Pentacrinus decorus (Pl. XXXL. figs. 1, 3; Pl. XXXIV. fig. 1; 
Pl. XXXVL), in which the cirri are usually directed downwards. In this respect, there- 
fore, Pentacrinus wyville-thomsoni presents an approach to the genus Metacrinus, in 
1 The Atlantic, vol. ii. p. 126. 
2 Much of what has been written above would have appeared more suitably in Chapter II. pp. 18-22, where the 
mode of life of the Pentacrinide 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. 
