74 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



involving the entire dorsal surface of the penultimate segment; this is usually more or 

 less broadly rounded, rarely pointed. The terminal claw is usually about as long as the 

 penultimate segment and is stout, rapidly tapering, moderately curved, and usually 

 with a blunt tip. 



The ends of the basal rays are visible as small more or less irregular tubercles in 

 the interradial angles beneath the inverted V formed by the narrow lateral ends of 

 adjacent radials. 



The radials are concealed by the centrodorsal except for the narrow lateral ends 

 that meet above the ends of the basal rays. Narrow and shallow slitlike subradial 

 clefts are present. The IBrj are short and bandlike with the proximal and distal borders 

 slightly curved and parallel and the lateral ends in apposition with those of their neigh- 

 bors on either side. The IBr 2 (axillaries) are short, about three times as broad as long, 

 rhombic with pointed or slightly truncated angles, and in lateral apposition. The 

 IIBr series, which are 2, resemble the IBr series but are somewhat longer. The 

 proximal and distal borders of the ossicles of the division series may be slightly and 

 broadly thickened, but there is no trace of a median carination or other modification 

 of the surface. The dorsal surface is moderately convex. 



The 13 arms are about 125 mm. long. The first brachials are short, about four 

 times as broad as long, slightly longer exteriorly than interiorly, with the proximal and 

 distal borders straight and almost parallel. They are interiorly united for their whole 

 length and externally are in contact with their neighbors against which they are rather 

 narrowly flattened. The second brachials are larger than the first, irregularly quadrate 

 or triangular with the inner side reduced to a point and the proximal border rather 

 strongly curved. The first syzygial pair (composed of brachials 3+4) is oblong, 

 usually about twice as broad as long, with the hypozygal and epizygal of the same size. 

 The next five or six brachials are oblong, about three times as broad as long, those 

 succeeding becoming wedge-shaped and soon almost as long as broad, remaining of the 

 same proportions until the terminal portion of the arm, where they become somewhat 

 elongated. The oblong brachials at the base of the arm are slightly constricted cen- 

 trally and there is a slight suggestion of indistinct broad and low articular tubercles, 

 so that this portion of the arm appears somewhat irregular and rugose. There is no 

 trace of carination or other ornamentation of the dorsal surface. On about the twelfth 

 brachial the middorsal portion becomes elevated in a V-shaped area with a rounded 

 summit, the apex of the V being in the middle of the proximal border and the narrow 

 side, which is finely serrate, on the distal border. At first these V-shaped elevations 

 alternate on either side of the median line, but they soon become aligned along the mid- 

 dorsal line of the arm. The arm now becomes compressed laterally, after about the 

 proximal third becoming narrow and high with a conspicuous narrowly rounded median 

 carination which is higher on the distal than on the proximal ends of the brachials so 

 that the arm appears serrate in lateral view. 



Syzygies occur between brachials 3+4 and 13 + 14 or 14+15, and distally at 

 intervals of from 6 to 12 muscular articulations. 



PI is 6.5 mm. long with 15 segments, only slightly larger than the pinnules follow- 

 ing, tapering evenly and regularly from the base to the tip. The first segment is some- 

 what broader than long, those following slowly increasing in length, becoming as long 

 as broad on the sixth or seventh and somewhat longer than broad distally. The pinnule 





