REPORT ON THE CRINOIDEA. 335 



joint-faces (PI. XXXII. fig. 3 ; PI. XXXYII. fig. 22) is, however, very much the same 

 ill the two species. 



The minor characters of Pentacrinus decorus, i.e., those wliich ai-e of least import- 

 ance for systematic purposes, present a very remarkable amount of variation. The 

 number of internodal joints may vary almost as much as in Pentacrinus asterius, 

 some of the indi\'iduals having the internodes as short as those of Pentacrinus hlahei 

 (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 eases. 



The internodal joints are generally quite smooth externally ; but they occasionally 

 bear groups of iiiterradial 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 cii'rus-sockets (PI. XXXV. fig. 1 ; PL XXXVI. 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 Pis. XL and XXXIV.). 

 The longest which I have seen, consisting of fifty internodes, measures 80 cm. Sii" WyviUe 

 Thomson mentioned one which was about two feet in length ;^ and this seems to have 

 been the original of a drawing which was made for him by Mr. AVild. He spoke of the 

 final joint, which is the epizygal at about the forty-second node, as being woni and 

 rounded ; and having subsequently found several other examples in the same condition, 

 he expressed his belief that disengagement at a syzygy is 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. JMoreover, 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 cm. 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 1S64, p. 7. 



