348 THE VOYAGE OF H.M.S. CHALLENGER. 



lono-est between the eleventh and twelfth nodes. The interarticular pores end between 

 the eiarhth and tenth nodes. 



Basals prominent, more or less extended downwards. Radials four, the second a 

 syzygy. ' Earely more than four divisions of the rays, giving forty or fifty arms, which 

 consist of about one hundred joints beyond the last axillary, the basal ones slightly over- 

 lapping. Primary arms of six to eight, or sometimes ten distichals, of w^hich the second 

 or third is a syzygy. Secondaries of ten to fifteen (usually twelve to fourteen) palmars, 

 the third generally a syzygy. Tertiary arms rare, consisting of fourteen to twenty-six 

 (usually eighteen to twenty) joints, the third of which is a syzygy. In rare cases there 

 is another axillary after twenty joints more. There is generally a syzygy in the third 

 brachial of the free arm, another betw^een the seventh and twenty-sixth, and others at 

 intervals of six to eighteen joints. The distichal pinnules have large outer joints, and 

 are therefore larger on the whole than those on the radials, though the basal joints are 

 generally less massive than in the radial pinnules. All the pinnules, and especially the 

 lower ones, have a serrate dorsal edge. The disk bears numerous small plates, which are 

 not very closely set, except in the anal interradius. The ambulacra of the disk and arm- 

 bases are supported by irregular elongated plates, the latter being distinctly above the 

 arm-groove, with a few ambulacral plates at their sides. The brachial ambulacra pro- 

 tected by smaller bifid plates, which become differentiated on the pinnules into covering 

 and side plates. 



Colour when fresh — the stems almost white, and the crowns light yellow or light 

 reddish-orange (Moseley) ; in spirit, white. 



Localitij. — Station 192, September 26, 1874 ; in the Arafura Sea, ofi" the Ki Islands; 

 lat. 5° 49' S., long. 132° 14' E. ; 140 fathoms ; blue mud. Two specimens. 



RemarJcs. — This species is at first sight not unlike Metacrinus angidatus (PI. 

 XXXVIIL), having about the same number of internodal joints in the stem, and a nearly 

 identical arrangement of the arm-divisions. The stem-joints, how-ever, are very diff"erent 

 in the two types. The horizontal ridges, which are interrupted at the angles of the stem 

 in Metacrinus angidatus (PI. XXXIX. figs. 3, 11), are usually continued right round the 

 joints in Metacrimis cingidatus (PI. XLI. figs. 1,3); and they appear also as enlargements 

 of the angles of the nodal joints (PL XLI. fig. 2), which are much less sharp than in 

 Metacrinus angidatus (PI. XXXIX. fig. 4). As a rule too there are generally slightly 

 fewer joints between the successive axillaries of the dividing rays than in the latter species, 

 but the character of the arms and of the pinnules which they bear is very much the same 

 in both. 



The two specimens of Metacrinus cingulatus which were obtained by the Challenger 

 difier somewhat in their characters, and each exhibits a certain amount of variation. 

 In the smaller individual there is an irregularity in one of the rays. The fourth or 

 axillary radial is not articulated to the preceding joint, as is usually the case, but the two 



