ORINOIDEA—CLARK. ll 
as broad, and the antepenultimate may be somewhat elongated. The third and 
following segments are constricted centrally with the dorsal and ventral (and also lateral) 
profiles markedly and evenly concave and the flaring distal ends overlapping the bases 
of the succeeding segments all round, though somewhat more strongly dorsally than 
elsewhere. As the segments decrease in length distally the dorsal and dorsolateral 
portions of their distal borders become more strongly produced and at the same time 
finely spinous, with a prominent tooth in the middorsal line. On the short outermost 
segments the dorsal surface becomes sharply carinate. As a result of the production 
of the dorsal surface of the segments the dorsal profile of the outer half of the cirri is 
very strongly and conspicuously serrate. The opposing spine is very small, low, conical, 
and subterminal in position, rarely somewhat elongated. The terminal claw is as long 
as, or longer than, the penultimate segment, and is very slender and only moderately 
curved, 
The distal edges of the radials are even with the rim of the centrodorsal in the 
midradial line, but curve strongly upward in the interradial angles where they are 
considerably produced outwardly, the general surface of the interradial triangle formed 
by the anterolateral portions of two adjacent radials being deeply sunken. The edges 
of the radials are very finely spinous. 
The IBr, are exceedingly short and band-like, between six and eight times as 
broad as the median length, broadly chevron-shaped, with the lateral borders convergent 
distally. The lateral portions of the distal edge are more or less strongly armed with 
fine spines. The IBry (axillaries) are rhombic, somewhat broader than long, with all 
the sides rather strongly and almost equally concave. Their lateral angles project for 
some distance beyond the obtuse anterolateral angles of the IBr,. The anterior (distal) 
edges are finely spinous. 
The 10 arms are about 85 mm. long. The first brachials are five or six times as 
long exteriorly as interiorly. From the inner side their distal border runs parallel to the 
proximal border to beneath the posterior projection of the second brachial, then turns 
distally and runs at an angle of about 45° with the proximal border to the outer distal 
angle. The distal edge is roughened with numerous very small spines, the roughening 
being broadest in the middle. The second brachials are very much larger than the first 
and are irregularly quadrate. Their outer border is about as long as the outer border 
of the first. A small area, roughly a right-angled triangle with the hypotenuse 
coinciding with the distal border and the opposite angle proximal and median, is 
roughened with fine short spines. The first syzygial pair (composed of brachials 3 + 4) 
is almost oblong, but slightly longer interiorly than exteriorly, with the proximal and 
distal borders slightly concave. The central half of the distal border is somewhat 
produced and is armed with short spines, this production being broadest in the median 
line. The next four brachials are wedge-shaped with strongly concave ends, twice as 
broad as the median length, with the longer side about half again as long as the shorter. 
The distal border is abruptly everted, and the central half is strongly produced at right 
