62 BULLETIN S2, UNITED STATES NATIONAL MUSEUM 



about half again us long as broad, and the eighth is usually about one-third again as 

 long as broad. The following segments decrease in length, those in the terminal fourth 

 or fifth Mi" the cirri being nearly twice as broad as long. The eighth segment has the 

 dorsal portion of the distal edge very slightly produced and finely spinous. On the 

 segments succeeding this production of the distal edge becomes narrower and higher 

 and involves more of the dorsal surface, in the segments of the terminal portion of the 

 cirri narrowing into a high dorsal spine with a rounded dorsal crest. The first cirrus 

 segment commonly bears a small tubercle resembling those on the dorsal surface of the 

 centrodorsal. 



The ends of the basal rays are visible in the angles of the calyx as distinct tubercles, 

 or as a continuation ol the interradial crests on the centrodorsal. 



The distal portion of I he radials is visible as a narrow curved hand just beyond 

 the rim of the centrodorsal. The anterolateral angles are separated by a slight notch, 

 and may he produced into a small high tubercle. The IBri arc narrow, four times as 

 broad as Inn;;, with the proximal and distal borders parallel. The lateral edges are 

 produced and slightlj everted, and arc broadly scalloped or bear two or three blunt 

 tubercles. The proximal border may be either unmodified or slightly scalloped, and 

 may bear a. tubercle ai or near the posterolateral angles. A conspicuous narrowmedian 

 keel with the cresl evenly convex i:i lateral view occupies the midline. The IBr 2 

 (axillaries) are low, three times as broad as long, with the lateral edges not very much 

 shorter than those of the IBri. The distal edges are slightly and narrowly thickened, 

 and the posterolateral angles are more or less produced and irregularly scalloped. A 

 icuous narrow keel, of which the crest as seen in profile is straight, occupies the 

 entire median line of the ossicle. The II Br series are 2 and. resemble the IBr series, 

 but are proportionately slightly longer with the borders of the component ossicles less 

 irregular. The proximal and distal borders are very slightly everted. 



The 20 arms are 100 mm. long. They are narrow at the base and increase slowly 

 in width up to the tenth or twelfth brachial, thence very gradually tapering distally. 

 The first brachials are half again as long exteriorly as interiorly, and about twice as 

 broad as the exterior length. The inner edges are slightly produced, forming flangelike 

 margins which meet above the apex of the axillaries. There is a conspicuous narrow 

 median keel. The proximal border is slightly and narrowly everted. The second 

 brachials are slightly larger with the niter side slightly longer and the inner side shorter. 

 They hear a conspicuous median keel, and the proximal and distal borders are slightly 

 and narrowly everted. The first syzygial pair (composed of brachials 3+4) is from 

 one-third to one-half again as broad as long. Both the hypozygal and the epi/.ygal have 

 a narrow median keel h Inch is not so high as that on the brachials preceding. The next 

 four brachials are Blightly wedge-shaped, and are about three times as broad as the 

 median length; each has a Blight, but distinct, narrow median keel. The following 

 brachials become \ ery obliquely wedge-shaped, or almost triangular, not quite twice as 

 broad as I he greater length, and distally gradually less obliquely wedge-shaped and 

 P. Each brachial hears a low narrow median keel with a rounded crest, The 

 distal .i the brachials are slightly produced and finely spinous, the spines being 



most conspicuous at the md of the median keel In lateral view the dorsal profile of 



the arm I rate. 



