158 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



The distal edges of the radials are even with the rim of the centrodorsal. The 

 IBrj are short, oblong, about four times as broad as long, with a well-marked median 

 tubercle. The IBr 2 are slightly longer than the IBr I( though similar. These two 

 ossicles together form a syzygial pair, which is nearly twice as broad as long, with the 

 lateral edges slightly turned outward. 



The five arms are 75 mm. long. The first and second brachials are slightly over 

 twice as broad as long with the distal edges rather prominent and with a rounded 

 median tubercle; their lateral edges, like those of the IBrj and IBr 2 , are slightly turned 

 outward, forming a narrow lateral border. The first syzygial pair (composed of 

 brachials 3+4) is not quite so long as broad, slightly longer on one side than on the 

 other, and bears a low rounded median keel. The next two brachials are wedge- 

 shaped, not so long as broad, and those following are triangular, about as long as 

 broad, soon becoming obliquely wedge-shaped and longer than broad, and distally 

 elongate and less obliquely wedge-shaped. The brachials as far as the sixth or seventh 

 have a low rounded median keel marked by a series of longitudinally elongate tubercles, 

 one on each brachial. From this point onward the keel becomes less evident and 

 assumes a zigzag course. It is traceable to at least the distal third of the arm. The 

 distal ends of the brachials in the proximal portion of the arm project somewhat, but 

 this feature dies away after about the middle of the arm. 



Syzygies occur between brachials 3+4, 8+9, and 13 + 14, and distally at inter- 

 vals of 3 muscular articulations. 



P c is 4 mm. long, stout and prismatic, composed of nine segments, which are about 

 as long as broad. PI is similar to P c but much stouter, 6 mm. long with 12 segments, 

 of which the first three are about as long as broad and the remainder are longer than 

 broad, though not elongated; the pinnule is rounded and all the segments overlap 

 strongly and have serrate distal ends. P ft resembles P t . The pinnules following are 

 about 4.5 mm. long, much more slender than those preceding, with about 12 segments 

 of which the first is very short, the next two are about as long as broad, and the re- 

 mainder are elongate with the articulations somewhat swollen and the lower segments 

 with overlapping and spinous distal ends. The distal pinnules are 9 mm. long, slender, 

 with the first segment short, the second about as long as broad, and the remainder much 

 elongated with expanded articulations. 



The disk is lacking. Sacculi are abundant and large on the pinnules, less abun- 

 dant and smaller along the brachial ambulacra. 



The color is purplish brown, lighter dorsally, the arms and pinnules banded with 

 purple and whitish, the cirri white, and the enlarged pinnules (P t and P a ) purple. 



Notes. A rather small and immature specimen in the Hamburg Museum may 

 be described as follows: The centrodorsal is thin discoidal with a flat dorsal pole 1 

 mm. in diameter. The cirri are arranged in a single irregular marginal row. The 

 cirri are XVII, 14-15, 5 mm. long. The fourth and fifth segments are the longest, 

 very slightly longer than the proximal width. The second-fifth segments are centrally 

 constricted with widely flaring distal ends which project strongly dorsally; this fea- 

 ture rapidly decreases distally and disappears after the eighth. The distal border of 

 the radials is slightly swollen, and is smooth or finely beaded. The proximal border 

 of the IBr t is slightly everted and bears a small but prominent median tubercle; the 

 distal edge is also everted, the eversion being thickened and slightly produced in the 



