350 THE VOYAGE OF H.M.S. CHALLENGER. 
articular surfaces of the wide and deep cirrus-sockets are limited to the nodal joints, 
which are markedly stellate in form, though their angles are not produced outwards. 
The infra-nodals are also deeply notched by the downward extensions of the cirrus- 
sockets. Cirri composed of about forty-five joints, almost all of which, and especially 
the basal ones, are wider than long. JInterarticular pores disappear at the thir- 
teenth node. 
The basals appear externally as rhomboidal knobs, but they extend laterally to meet 
their fellows in the re-entering angles of the calyx. Four radials, of which the first is 
relatively short and wide, and the second a syzygy. The rays divide four, and 
occasionally five, times, giving about ninety arms. These consist of about one hundred 
and ten joints above the tertiary axillaries, and, like the rays, are quite smooth at the 
base, only becoming serrate towards the extremities. Four or rarely six distichals in the 
primary arms; eight or ten palmars in the secondaries; and the tertiaries of eight to 
eighteen (usually twelve or fourteen) joints. The next division (when present) occurs 
after about fourteen or sixteen (ten to twenty-four) joints more. The third joint after 
each axillary is usually a syzygy. Another between the tenth and thirtieth brachials, 
and then an interval of five to thirteen joints between successive syzygies. 
The two radial pinnules, and also those on the lower distichals, have one or two 
massive basal joints; but the following joints, though long and moderately thick, are 
very much flattened laterally, so that the dorsal surface is reduced to a mere edge. The 
longest pinnules are those immediately above and below the distichal axillary, and are 
less compressed than their predecessors, so that the joints are more uniform in appear- 
ance, though the lower ones are relatively large and cuboidal. The palmar pinnules are 
all long ; but the size begins to diminish beyond the axillaries, rapidly at first, and after- 
wards somewhat slowly. 
The disk is thickly covered with plates which are small and more closely set upon the 
anal tube than elsewhere. Brachial ambulacra not much above the arm-groove, and 
supported by bifid plates which are differentiated into side and covering plates about the 
middle of the pinnules. 
Colour in spirit—calyx and arm-bases grey ; arms and stem nearly white, but the tips 
of the arms light brown. 
Remarks.—The fine specimen which forms the subject of the above description has 
unfortunately lost most of its arms in the usual way, viz., by fracture at one or other of 
the lower syzygies. In the frequency of its ray-divisions, in the constant presence of 
supra-palmars, and in the diameter of its stem, it ranks among the largest types of 
recent Pentacrinide, and I have much pleasure in associating it with the well known 
name of Mr. John Murray. 
The species which it most nearly resembles is Metacrinus nobilis, from Station 192, 
near the Ki Islands; though the two forms differ considerably in the characters of the 
