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



articular surfaces of the wide and deep cirrus-sockets are limited to tlie 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. Interarticular 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 diflerentiated into side and covering plates about the 

 middle of the pinnules. 



Colour in spii-it — calyx and arm-bases grey ; arms and stem nearly white, but the tips 

 of the arms light brown. 



RemarJcs. — The fine specimen which forms the sul:)ject 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 Pentacrinid*, 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 difi"er considerably in the characters of the 



