PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 609 



lapping ends of the segments have a narrow glassy border which is widest hi the dorsal 

 half where it runs to the dorsal spine. In the distal third of the cirri the segments 

 gradually decrease hi length so that the ninth from the end of the cirrus is about twice 

 as long as broad, and the penultimate is only slightly longer than broad. The opposing 

 spine is conical, glassy, arising from most of the dorsal surface of the penultimate seg- 

 ment and with its apex in the same line as the distal border of that segment. The 

 terminal claw is somewhat longer than the penultimate segment and is moderately and 

 evenly curved. 



The radials are visible as narrow strongly curved bands above the run of the 

 centrodorsal. Each radial is separated from those on either side by a V-shaped notch. 

 The IBri are short, about six times as broad as long in the median line, with the lateral 

 borders about twice as long as the median length. The IBr 2 (axillaries) are rhombic, 

 about as long as broad, with the distal angle produced and acute and the distal sides 

 strongly concave. The distal edges of the IBri and IBrj and the lateral portions of the 

 proximal edge of the IBr 2 are strongly everted and coarsely and irregularly serrate. 

 The IBr series are well-rounded dorsally and are not in lateral contact. 



There are 10 arms. The first brachials are four or five times as long exteriorly as 

 interiorly. The portion from the inner end to the median line is narrow with parallel 

 sides; from the median line to the outer border the proximal and distal edges diverge 

 rapidly. The distal edge is strongly everted and serrate. The second brachials are 

 much larger than the first, irregularly quadrate with a strong rounded proximal process 

 deeply incising the first brachials. The distal edge is strongly everted and serrate. 

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

 distal border is armed with a row of conspicuous and rather long and broad more or less 

 webbed spines. The next five or six brachials have the distal edge very strongly spinous, 

 but on those following the distal edge is smooth and not produced. 



Syzygies occur between brachials 3 + 4 and 10+11, or 3+4, 9 + 10, 13 + 14, and 

 16+17, in the two arms preserved beyond the base. 



PI is about 8 mm. long, slender and becoming very delicate and filiform distally, 

 with 21+ segments. The first five segments are roughly about as long as broad with 

 broadly rounded angles and small tufts of spines on the middle of the distal ends. The 

 following segments rapidly become elongated, those in the distal third of the pinnule 

 being five or six times as long as broad with expanded and overlapping distal ends. 

 P a is similar to PI. P 2 and the following pinnules are much stouter than PI about twice 

 as broad in the proximal portion but only the bases are preserved. The earlier seg- 

 ments bear a conspicuous broad spine or tuft of spines at the distal end on the side 

 toward the arm tip. 



The spicules in the perisome of the pinnules are conspicuous and very character- 

 istic. There is only a single row. The spicules are long, about two-thirds as long as the 

 pinnule segments, rather slender, and abruptly bent or curved upward at a slight angle 

 at about the middle. In some cases the upper branch of the bifurcation bears two long 

 spines on the outer side and ends in a shortly bifurcated tip while the lower branch, which 

 is about half as long as the upper, bears a single spine about half as long as the spines on 

 the upper branch and ends in a bifurcated tip; the upper branch of the bifurcation is 

 nearly a quarter the length of the spicule. In other cases the upper branch of the bi- 

 furcation bears two processes each with a bifurcated tip and itself ends hi a bifurcated 

 tip, while the lower bears one branch with a bifurcated tip, or is without a lateral branch. 



