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length and becoming nearly, sometimes quite, as long as broad on the fifth; the next two or 
three are similar; the following very gradually decrease in length so that those in the outer 
fourth of the cirri are about twice as broad as long; in their outer fourth of fifth the cirri 
taper very gradually so that the tip is comparatively slender. The distal edges of the segments 
all around are everted and prominently overlapping. From the tenth segment onward there 
is evident a carination of the mid-dorsal line, at first affecting only the distal part of the 
segments but soon rising into a high sharp keel occupying the entire length of the dorsal 
surface, the crest of which is parallel to the long axis of the cirri. In the distal portion of the 
cirri, beginning on the tenth-eighteenth (usually on the fourteenth or fifteenth) segment before 
the terminal claw a small tubercle appears on either side of the median carination near the 
lateral borders of the segments as viewed dorsally; these tubercles rapidly elongate and develop 
into supplementary keels parallel to the median keel and similar to it, but lower. 
The radials are even with the edge of the centrodorsal in the median line, but are 
strongly produced in the angles of the calyx where they separate widely the bases of the IBr^; 
the ventral edge of this anterior process, which is straight and not spatulate nor otherwise 
modified, is equal in length to the lateral edges of the IBr^; the cirrus sockets are more or 
less supported by the radials as in Oreonietra mariae. 
The arms are from 30 to 40 in number, 70 mm. to 75 mm. long, arranged in 2, i, i, 2 
or 2, 2, 2, 2 order; some rays may bear as many as nine arms in which case, as in all cases, 
the extra axillary is external ; the division series extend themselves horizontally from the centro- 
dorsal (that is, at right angles to the dorsoventral axis of the animal) and are very widely 
separated ; all of the division series are 2 ; they are very narrow and strongly rounded ; the 
extreme ventrolateral border of the ossicles of the division series is produced into a thin flange 
with a smooth and thin outer border which runs from the distal edge of the interradial production 
of the radials along the sides of the ray as far as the second brachial ; but this is only visible 
dorsally as far as the IBr axillary; from the ends of the interradial processes from the radials 
these flanges are (viewed ventrally) perfectly parallel as far as the IIBr axillary, but as the 
IIBr series make a very considerable angle with each other the flanges necessarily disappear 
from dorsal view at the IBr axillary. The union of the ossicles of the IBr series is extremely 
close, appearing like a syzygy, but the union of the ossicles of the other division series is not 
so modified. The proximal and distal borders of the ossicles of the division series, including 
the distal borders of the IBr axillary, are prominendy everted, but smooth and not spinous, 
giving the division series a singularly and characteristically rugged appearance. 
The arms resemble those of N. i>iulticolor, the brachials after the eighth or ninth being 
about as long as broad, triangular, with the outer edge somewhat convex; the distal edges 
of the brachials are produced, thin, and finely spinous, this production being highest on the 
side bearing the pinnule (toward the longer side) where it begins abruptly; in the outer part 
of the arm it gradually becomes less and less marked, beginning less and less abrupdy. 
Syzygies occur between brachials 3 + 4, 11 + 12 to 15 + 16 (usually i i + i 2 or 12 + 13), 
and again after 4 oblique muscular articulations; the distal intersyzygial interval is 3 oblique 
muscular articulations. 
