o1l4 THE VOYAGE OF H.M.S. CHALLENGER. 
N.B,.—Examples of this species have been distributed to several museums, and only 
a few have come into my hands; so that the first three of the measurements given above 
must not be taken as indicating the whole range of variation throughout all the individuals 
which were dredged by the “ Porcupine.” 
Stem smooth and moderately robust, but of no great length. The upper part is 
pentagonal with rounded angles ; but the lower portion of an old stem is almost perfectly 
circular. Thirty to forty, and occasionally more, internodal joints with crenulated edges 
which are less distinct below, Nodal joints enlarged, with sharp angular ridges which 
stand out prominently between the cirrus-sockets. These are transversely oval, and 
occupy the whole height of the nodal joint, which projects outwards over the upper edge 
of the infra-nodal, while the supra-nodal is slightly grooved to receive the bases of the 
stout cirri. These consist of about eighteen tolerably equal, smooth, and thick joints, the 
lowest of which are broader than their successors, especially in mature individuals. 
Terminal claw small, without an opposing spine. The lowest limit of the interarticular 
pores is a little on either side of the fourth node. 
Basals pentagonal, but sometimes approaching the triangular, wider than high, and 
forming a closed ring. The rays and their subdivisions in close lateral contact, the first 
five or six joints after the distichal axillary having flattened sides, The two outer radials 
united by syzygy. Fourteen to twenty-two arms, distichal axillaries being often absent, 
and palmars very rare. Primary and secondary arms each of two joints united by syzygy ; 
the first two brachials united in the same way, the epizygal bearing a pinnule. The arms 
of about seventy smooth, oblong joints in which syzygies are very rare. 
The first pinnules quite short, consisting only of nine or ten joints, the lowest of 
which are broad and flat, the later ones longer and more slender. The following pinnules 
increase rapidly in size, and soon become long and tapering, consisting of about twenty 
smooth, elongated joints, the lowest of which are slightly flattened. Disk completely 
covered with a pavement of small plates, as is the brachial perisome above the muscular 
bundles. Arm-groove moderately wide, and bordered by a discontinuous series of 
ambulacral plates, The pinnule-ambulacra have covering plates, but very ill defined 
side plates. 
Colour grass-green, becoming white in spirit, which acquires a purplish-red tinge. 
Locality H.M.S. “‘ Porcupine,” 1870. Station 17; lat. 39° 42’ N., long. 9° 43’ W.; 
1095 fathoms ; ooze; bottom temperature, 39°°7 F. About twenty specimens. 
Also the “Talisman,” 1883; off the Morocco Coast: and again off Rochefort ; 
lat. 45° 59’ 30” N., long. 6° 29’ 30” W. of Paris; 1500 metres (800 fathoms). 
Remarks.—This fine species was first obtained by Dr. Gwyn Jeffreys during the 
“Porcupine ” expedition of 1870 ; and it was dedicated by him to his friend and colleague 
Sir Wyville Thomson in the general account of the voyage which was published in the 
