ait, 
REPORT ON THE CRINOIDEA. 399 
joint-faces (P!. XXXII. fig. 3; Pl. XXXVI. fig. 22) is, however, very much the same 
in the two species. 
The minor characters of Pentacrinus decorus, i.e., those which are of least import- 
ance for systematic purposes, present a very remarkable amount of variation. The 
number of imternodal joints may vary almost as much as in Pentacrinus asterius, 
some of the individuals having the internodes as short as those of Pentacrinus blaker 
(seven joints), while in others they may consist of sixteen joints as in Penta- 
crinus asterius; and this character sometimes runs through the whole stem, so that 
at first sight two individuals will look as if they belonged to entirely distinct species, 
especially if the development of the basals and arm-divisions be also different in the 
two cases. 
The internodal joints are generally quite smooth externally ; but they occasionally 
bear groups of interradial tubercles at more or less regular intervals, and these tubercles 
sometimes.appear on the nodal joints, thus increasing the prominence of their angles 
between the cirrus-sockets (Pl. XXXYV. fig th je Ply XV figs. 1, 2). Two individuals 
are remarkable for the absence of some of the cirri on the stem. Thus in a specimen repre- 
sented in Pl. XXXVI. fig. 1, one of the cirri is missing at the fourth node, no socket 
having been developed at all; while in another shown in Pl. XXXVII. fig. 2, there are 
no cirrus-sockets along one face of the stem to as far down as the twelfth node ; and at 
the eleventh node another socket is absent, so that there are only three cirri at this 
node, the empty faces of the stem intervening between the cirrus-bearing ones exactly 
as they do in those nodal joints of Pentacrinus alternicirrus which bear three cirri 
(Pl. XXV.; PL XXVI. figs. 13, 14; PL. XXVII. fig. 2). 
The stem of Pentacrinus decorus, though more slender than that of Pentacrinus 
asterius, seems like it to grow to a considerable length (compare Pls. XI. and XXXIV.). 
The longest which I have seen, consisting of fifty internodes, measures 80 cm. Sir Wyville 
Thomson mentioned one which was about two feet in length 1 and this seems to have 
been the original of a drawing which was made for him by Mr. Wild. He spoke of the 
final joint, which is the epizygal at about the forty-second node, as being worn and 
rounded ; and having subsequently found several other examples in the same condition, 
he expressed his belief that disengagement at a syzygy 1s habitual. This is doubtless 
often the case as in Pentacrinus wyville-thomsoni and other species (ante, pp. 18-20), 
though I have not myself met with any specimens in this condition. Moreover, it 
appears certain that this species may be sometimes permanently fixed. Captain Cole’s 
observation that they may be attached to telegraph cables by the basal extremity of the 
stem spreading slightly has been noticed already ; and the individual mentioned above 
as having a stem 80 em. long (which is now in the British Museum) was found by him 
attached in a slightly different way. The stem is detached from its basal portion at the 
1 Sea Lilies, The Intellectual Observer, August 1864, p. 7. 
