REPORT ON THE CRINOIDEA. 365 
of about forty joints, some of which (after the short and wide ones at the base) are 
longer than broad. The dorsal edge of the middle joints is slightly serrate, but the later 
ones become almost smooth. Interarticular pores end about the ninth node. 
Basals pentagonal and forming a closed ring, but very convex in the centre, so as to 
appear like rhomboidal knobs resting on the interradial ridges of the stem. Radials six, 
very convex, the second and fourth syzygies. Rays well separated laterally, and divide 
four times. Arms twelve or more to the ray, slightly serrate in the medio-dorsal line, 
especially in the lower divisions. Primaries of six or eight (rarely ten) joints ; second- 
aries of eight to fourteen palmars; tertiaries of sixteen to twenty-eight joints. The 
third joint after each axillary is a syzygy, and the next syzygy in the free arms is 
anywhere between the tenth and twenty-fourth joints ; after which the syzygies follow at 
intervals of five to fourteen joints. 
The radial pinnules, especially the first one, mostly have wide and massive basal 
joints with thickened edges ; but the middle joints are more compressed and the terminal 
ones slender. The distichal pinnules are also stout and composed of large joints; but 
the following ones consist of compressed and more elongated joints, the first two of which 
are considerably wider than the rest until some little way beyond the last axillary. 
The disk is covered with numerous small plates, which are much smaller and more 
closely set in the anal interradius than elsewhere. Brachial ambulacra above the arm- 
grooves, and protected by irregular plates from which the covering plates and large 
pointed side plates are developed on the pinnules. 
Colour—of a uniform dusky purple when fresh (Moseley); greyish-white in 
spirit. 
Locality.—Station 170a, July 14, 1874; near the Kermadee Islands; lat. 29° 45’ S., 
long. 178° 11’ W.; 630 fathoms ; volcanic mud; bottom temperature, 39°°5 F. 
Remarks.—Three examples of this elegant little species seem to have been obtained 
by the Challenger. One of them is quite young (Pl. LI. fig. 1), while the other two were 
in a much mutilated condition. The dissected calyx figured on Pl. L. figs. 5-18 appears 
to belong to the fragment represented on fig. 1 of the same Plate. It is certainly not 
the same as that of which the disk is shown in fig. 2. This last and a few detached arms 
have served as the basis of the foregoing description. The only species with which 
Metacrinus nodosus is liable to be confused is the little Metacrinus costatus from off the 
Meangis Islands (Station 214). For Metacrinus wyvillii, which also has six radials and 
about the same number of internodal joints, is altogether much larger and more robust. 
But it has a smaller number of arms than either Metacrinus costatus or Metacrinus 
nodosus. The difference between these two last lies chiefly in the characters of the stem, 
both of them having twelve or more arms on the ray, owing to the presence of axillaries 
on the outermost of each set of four tertiary arms, as well as on some of the inner ones 
occasionally. The pinnules are generally similar in the two types, and the peculiar 
