750 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



Description [by A.M.C.]. The centrodorsal is conical with the apex quite acute 

 in one of the three syntypes and blunted in the others. In the two larger ones it is 

 about 2 mm. in basal diameter and 1.5 mm. high. In the smaller one the height is 

 less than half the basal diameter. The cirri number about XXV in two and XXX in 

 the third. Their sockets do not have conspicuously raised rims. 



According to Carpenter the cirri have 15 to 18 segments. No complete cirri with 

 more than 13 segments now remain (1957). The one with 13 segments measures 10 mm. 

 in length. It arises from the middle row of sockets on the centrodorsal, above the 

 peripheral row in the specimen with XXX cirri. The second segment is already 

 slightly longer than wide. The fifth and sixth segments are the longest and are just 

 under four times as long as their median widths. The outer segments are relatively 

 shorter, the antepenultimate is about three times as long and the penultimate 

 twice as long as its median width. The fifth segment of a broken peripheral cirrus, 

 much larger than the complete one, is over four times as long as wide, while the proximal 

 segment of a detached peripheral cirrus measuring 11 mm. hi length and lacking both 

 ends is nearly four and a half tunes as long as broad. A detached apical cirrus with 

 10 segments, probably lacking about 4 at the base, measures 5.5 mm. Its segments are 

 all more or less expanded on the dorsal side at their outer ends, more particularly the 

 distal segments. This flaring of the segments is much less marked in the longer cirri. 



The distal edges of the radials extend only very slightly beyond the rim of the 

 centrodorsal. The IBr, are short, rather strongly convex dorsally, deeply incised in 

 the median line and only partially free laterally. The IBr 2 are rhombic, as long as or 

 longer than broad, the proximal angle being very pronounced. The distal borders 

 are concave. 



The 10 arms were probably about 35 mm. long. From the proximal edge of the 

 IBrj to the second syzygy at 9 + 10 measures 7.5 mm.; the width at the first syzygy 

 is 1 . 1 mm. The brachials are fairly smooth. In one of the larger syntypes the brachials 

 are thickened and slightly flared at their distal ends while in the other the dorsal 

 profile of the arm is quite smooth. 



The third syzygy is rather irregular in position but is most often between brachials 

 16 + 17. The distal interval is usually 3 or 4 muscular articulations but may be more 

 or less. 



The proximal pinnules are slender and tapering, the segments of PI particularly 

 having very little expansion at the joints. According to Carpenter PI and P a have 10 

 to 12 segments but a PI with 9 segments, as shown in the Challenger report figure, 

 appears to be complete or only lacks a single segment, though a P a with 9 segments 

 may have lost one or two. Both these pinnules measure 3 mm. in length. The first 

 segment of PI may be as long as wide or longer and the following segments are progres- 

 sively longer. P 2 in the two larger specimens bears a well-developed gonad, usually on 

 the third to fifth segments. There are 8+ segments, probably about 10, which are 

 relatively narrower than those of Pj and a little more swollen at the joints. The 

 length is a little greater than that of PI. The distal pinnules are longer. 



Locality. Challenger station 147; between Marion Island and the Crozets, south 

 of the western Indian Ocean (lat. 4616' S., long. 4827' E.); 2925 meters; temperature 

 1.22 C.; diatom ooze; December 30, 1873 [P. H. Carpenter, 1887, 1888] (3, B.M.). 



Remarks. Eleven specimens of this species were taken by the Challenger, of which 

 three are preserved in the British Museum. 



