EEPORT ON THE CRINOIDEA. 369 



in the tabular key to the species which embraces all the types of this genus that have yet 

 been discovered. 



The individual described above is the only specimen of any kind of Crinoitl which was 

 obtained at Station 209 ; and it has fortunately suffered much less injury than many of 

 the larger types dredged by the Challenger. I did not succeed in finding any Mijzostoma 

 upon it ; but a Scalpellum is attached to its stem, and several individuals of Vei-r-uca to 

 the cirri, on one of which a small Avicida was fixed by its byssus. 



11. Jletacrinus tuberosus, n. sp. (PI. LIII. figs. 1-G). 



Three species [Metacrinus angulatus,Metacrinus nohilis, Metacrinus cingulatus), repre- 

 sented by " about a dozen individuals,"' were dredged by the Challenger at Station 192, off" 

 the Ki Islands. Together with these there came up a fragment of a stem which I cannot 

 refer to either of these species, nor to any other Metacrinus yet known. It presents a 

 curious combination of certain features which are characteristic of the stems of Metacrinus 

 angulatus, Metacrinus costatus, and Metacrinus nohilis respectively, three very distinct 

 species from widely separated localities on diff'erent sides of the equator (Ki, Meangis, 

 and Kermadec Islands). I have no hesitation in regarding it as belonging to another 

 species of the genus, although the characters of its calyx are as yet unknown. 



It cannot belong to a Pentacrinus on account of the upward extension of the cirrus- 

 sockets on to the supra-nodal joints (PL LIII. fig. 2), a character which is eminently 

 distinctive of Metacrinus. 



The fragment consisted of five complete internodes, one of which was sacrificed to 

 anatomical purposes, so that only four are shown in the figure (PL LIII. fig. 1). Each 

 internode consists of seven slightly crenulated joints. The five middle ones are as usual 

 different from those immediately above and below the nodes. The}' are sharply 

 pentagonal in form, with a somewhat prominent tubercle in the middle of each side 

 (PL nil. figs. 4, 6) ; while the angles are sharp and slightly produced outwards beyond 

 the ends of the petaloid areas, as is to some extent the case in Metacrinus angulatus and 

 3£etacrinus costatus (PL XXXIX. figs. 3, 8, 10, 11 ; PL XLIX. figs. 3, 4). This is still 

 more evident in the nodal joints (PL LIII. fig. 3) as it also is in the other two species 

 (PL XXXIX. figs. 3-5 ; PL XLIX. fig. 5), and more distinctly in Metacrinus nodosus, 

 the internodes of which are not specially produced at the angles (PL LI. figs. 8-10). 

 The consequence is that the stem of Metacrinus tuberosus, Like that of Metacrinus 

 angulatus and Metacrinus costatus, is traversed by prominent interradial ridges 

 (PL XXXVIIL; PL XXXIX. figs. 3, 11; PL XLIX. figs. 1, 3; PL LIIL figs. 1, G). 

 The nodal joints have somewhat deeply hollowed cirrus-sockets which have relatively 

 wide facets, and encroach lioth on the supra- (PL LIII. fig. 2) and on the infra-nodal 



1 See R. V. Willemoes Suhm, Briefs von der Challenger Expedition, No. iv., Zdtschr. /. vdss. Zool, Bd. xxvi. p. liii., 

 1876. 



(zool. chall. EXP.— part xxxil — 1884.) li 47 



