gQ4 BULLETIN 82, UNITED STATES NATIONAL MUSETIM VOLDMB 1 



and the distal are half again as long as broad, arranged in 15 columns on the centro- 

 dorsal; the arms arc about 45 mm. long; P, is 8 mm. long, with 24 segments; Pj is about 

 5 mm. long, with 12+ segments. 



Description. — The centrodorsal is conical, 2.2 mm. in diameter at the base and 

 2.1 mm. from the apex to tlie rim. The tip, in side view the apical fourth, is papillose, 

 the obsolete cirrus sockets being occupied \>y stout cylindrical papillae with spinous 

 or roughened tips. The cirrus sockets are arranged in 15 crowded but regidar columns 

 of 3 or 4 each; the outer columns of the radial areas are less closely crowded against 

 those of adjacent radial areas than they are against the central column. 



The cirri are about LX, 17 to 28 (usually 20 to 25), from 15 to 30 mm. long. The 

 first segment is short, the second is nearly or quite as long as broad, tlie third is twice 

 as broad as the median width or longer, and the fourth to sLxth or seventh are about 

 five times as long as broad. Those following slowly decrease in length so that the 

 terminal are about half again as long as broad. The longer proximal cirrus segments 

 have the distal end sHghtly enlarged and slightly overlapping. As the segments de- 

 crease in length this feature becomes somewhat more pronounced on the dorsal side, 

 forming a narrowly rounded production of the distal dorsal edge that appears as a 

 slight spine in lateral view. The opposing spine is small and poorly developed, terminal 

 in position. The terminal claw is about as long as the penultimate segment, moder- 

 ately slender and moderately and evenly curved. 



The distal edge of the radials is even with the rim of the centrodorsal in the radial 

 line but interradially is much produced anteriorly, so that the anterolateral angles of 

 the radials separate slightly the bases of the IBri. The IBr, are short, about six 

 times as broad as the median length and twice as long laterally as in the median line; 

 the dorsal surface is slightly concave and the proximal and distal edges are narrowly 

 prominent, but unmodified. The lateral borders curve inward so that the IBri are 

 narrower distally than proximally. The lateral borders make with those of the ad- 

 jacent IBri an angle of about 45°. The IBrj are turned outward so that the mid- 

 dorsal line Ues at an angle of about 90° with the dorsoventral axis of the animal. The 

 IBr2 (axdlaries) are rhombic, slightly broader than long, with the distal and lateral 

 angles acute and the distal sides strongly concave. A strong rounded proximal process 

 incises the IBr,. The lateral angles extend beyond the laterodistal angles of the IBr,. 



The 10 arms are about 45 mm. long. The first brachials are short, about three 

 times as long externally as internally. The proximal and distal edges are parallel from 

 the inner side to the middle line, then diverge rather strongly to the outer side. The 

 inner sides he at riglit angles to the midradial line, the inner sides of two adjacent 

 first brachials lying in the same plane. The second brachials are much larger than the 

 first and are irregvdarly quadrate. Their inner angles are in contact over the pro- 

 cumbent inner sides of the first brachials, forming a large triangular water pore. The 

 first syzygial pair (composed of brachials 3+4) is slightly broader than long and slightly 

 longer interiorly than exteriorly; the sides are shghtly concave and the distal border 

 is somewhat thickened and finely spinous. The next four brachials are about half 

 again as broad as long with a concave dorsal surface and sides and the distal edge 

 everted and finely spinous. The second sj-zygial pair (composed of brachials 9 + 10) 

 is about as broad as the median length and half again as long outwardly as inwardly; 

 the distal edge is everted and finely spinous. The brachials following are obliquely 

 wedge-shaped, about as long as broad, soon becoming longer than broad and distally 



