15U BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



tapering somewhat distally. The opposing spine is represented by a small rounded 

 subterminal tubercle. The terminal claw is slightly longer than the penultimate 

 segment, very slender and sharp, and only slightly curved. The second and third 

 segments are rather strongly constricted centrally; the sixth and following have mod- 

 erately expanded and slightly overlapping distal ends ; both of these characters gradu- 

 ally die away distally. From the fifth segment onward the cirri are rather strongly 

 compressed laterally. 



The radials are just visible beyond the edge of the centrodorsal; their distal border 

 is swollen and turned outward, smooth or evenly tuberculated. The ossicles of the 

 IBr series (united in a syzygial pair) taken together form an element that is oblong, 

 not quite twice as broad as long; both the proximal and the distal borders are turned 

 outward, the former slightly, but the latter standing up at right angles to the general 

 surface of the segment, with a smooth and somewhat thickened edge; the proximal 

 edge may be more or less scalloped, and bears just within the border a prominent 

 rounded tubercle; the produced distal edge is thickest and most prominent in the 

 middorsal half, this portion being distally evenly concave; the remainder of the distal 

 edge may be broadly scalloped. 



The five arms are 90 mm. long. The first brachial is oblong, two and one-half to 

 three times as broad as long, with the proximal and distal edges slightly thickened and 

 everted. The second brachial is similar, but the distal edge is prominently everted, 

 especially in the central third where the eversion is thickened and distally concave, 

 standing up vertically from the dorsal surface of the segment. The first syzygial pair 

 (composed of brachials 3+4, or the fifth and sixth postradial ossicles) is slightly 

 longer on one side than on the other, about twice as broad as the lesser length; this 

 syzygial pair resembles the preceding syzygial pair (composed of the two elements of 

 the IBr series), but the tubercle just within the proximal border is only very slightly 

 indicated. The following three brachials are slightly wedge-shaped, about twice as 

 broad as the median length, with the distal borders everted as described for the second 

 brachial, but progressively less and less so. The following brachials are triangular, 

 about as long as broad, with slightly produced and overlapping distal edges. From the 

 fourth to the ninth brachials there is a low median carination which after the ninth 

 becomes the low rounded zigzag keel characteristic of the arms of all the species of this 

 genus, which is traceable throughout the entire length of the arms. 



PC is 6.5 mm. long, with 15 segments, rather stout basally, but tapering rapidly 

 to a very delicate tip, and strongly prismatic. The first segment is much broader 

 than long, the following gradually increasing in length and becoming about as long as 

 broad on the fourth or fifth, and terminally twice as long as broad. The second- 

 sixth segments have a narrow sharp carination the crest of which is straight and 

 parallel to the longitudinal axis of the pinnule; the outer edge of the prism formed by 

 the pinnule is sharp ; the outer surface of the pinnulars between the prismatic angles is 

 flat or very slightly concave. P, is similar, 6.5 mm. long, with 13 or 14 segments. 

 P ft is 11 mm. long, with 15 segments, much larger and stouter than those preceding, 

 tapering evenly from the base and becoming very delicate distally. The first segment 

 is much broader than long, the following gradually increasing in length and becoming 

 about as long as broad on the fourth and three times as long as broad terminally. 

 The second, third, and fourth segments have a low even carination. The second and 



