152 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



width, and the three following are about four times as long as the median width ; the 

 segments succeeding slowly decrease in length so that the antepenultimate is about 

 twice as long as broad and the penultimate is about as long as broad or slightly longer 

 than broad. The third segment is rather strongly constricted centrally. The next 

 few segments are moderately constricted centrally, and those succeeding have a 

 slightly concave ventral profile, but soon a less strongly concave dorsal profile. The 

 antepenultimate segment is practically oblong in lateral view. The opposing spine 

 is prominent and sharp, terminally situated, and is equal in height to about half the 

 distal width of the penultimate segment. The terminal claw is about as long as the 

 penultimate segment or slightly longer, and is slender and moderately and evenly 

 curved. 



The gently concave distal edge of the radials extends slightly beyond the rim of 

 the centrodorsal. The syzygial pair formed by the two elements of the IBr series is 

 oblong and half again as broad as long. The IBri has a low and broadly rounded 

 elevation occupying the median line. The IBr 2 has a corresponding but somewhat 

 less strongly marked midradial elevation, and the distal edge is slightly everted. 



The five arms are about 40 mm. long. The first brachial is short, oblong, about 

 four times as broad as long, of about the same size as the IBr t and with a similar 

 midradial elevation. The distal border is slightly everted. The second brachial is 

 slightly larger than the first, and is trapezoidal in shape; it bears a slight median 

 elevation in the proximal half or two-thirds, and the distal edge is slightly everted. 

 The syzygial pair formed by brachials 3+4 is slightly longer on the side bearing the 

 pinnule than on the opposite side, and is not quite twice as broad as long. The hypo- 

 zygal is oblong, nearly four times as broad as long, and the epizygal is longer on the 

 side toward the pinnule base than on the opposite side, in the midradial line being of 

 the same length as the hypozygal. The next two brachials are veiy bluntly wedge- 

 shaped, about two and one-half times as broad as the midradial length. After the 

 second syzygy the brachials become triangular, as long as or somewhat longer than 

 broad, but soon wedge-shaped again with less oblique ends, later becoming longer 

 with slightly concave sides. The brachials as far as the second syzygy have a low 

 and broadly rounded tubercle in the proximal portion. The succeeding brachials 

 have the middle of the dorsal line almost imperceptibly elevated. 



Syzygies occur between the elements of the IBr series, between brachials 3+4, 

 8+9, and 13+14, and distally at intervals of 3 muscular articulations. 



P c is 4 mm. long, with 11 segments, of which the first is short and trapezoidal, 

 half again as broad as the greater (inner) length, the second is almost oblong, twice 

 as broad as the median length, the third is about as long as broad, the fourth is half 

 again as long as the median length, and those following slowly increase in length, 

 becoming nearly three times as long as broad terminally. The third and following 

 segments have the distal edge very slightly everted. The pinnule is moderately 

 stout at the base and tapers evenly to the tip. The middorsal line is very obscurely 

 and roundedly elevated, scarcely suggesting the carination found in related species. 

 PI is 4 mm. long, with 12 segments, and resembles P c . P a is 8 mm. long, with 15 seg- 

 ments, roughly half again as broad at the base as P c , moderately slender and tapering 

 evenly to a fine tip. It is somewhat flattened laterally and is broadly rounded dor- 

 sally, not being prismatic. The first segment is from half again to twice as broad as 



