PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 315 



Syzygies occur between brachials 3 + 4, 9 + 10 (exceptionally 10+11), usually 

 16+17 (sometimes 15+16, more rarely 14 + 15 or 17 + 18), and distally at intervals 

 of usually 4, sometimes 3, more rarely 5, muscular articulations. 



The disk is about 12 mm. in diameter. 



P, is 18 mm. long, slender and flagellate, with 50 to 55 short segments. P 2 is 

 somewhat longer and slightly stouter, 22 mm. long with 53 segments, almost of the 

 same form but with slightly longer and somewhat thicker segments. P 3 is shorter, 

 17 mm. long, with 31 segments which are proportionately much longer. P 4 and P s 

 are about the length of P 3 or slightly shorter, with 25 to 30 segments of which the 

 proximal 5 or 6 are short and the remainder elongated. The remaining pinnules are 

 slender and their segments, with the exception of the two first, are much elongated. 

 The length of a pinnule on about the fifty-ninth brachial is 25 mm. 



Description of the type specimen. The centrodorsal is flattened hemispherical, 

 with a depression at the dorsal pole. 



The cirri are about LX, 33 mm. long, uniformly slender and laterally compressed; 

 the cirrus segments are for the most part elongated, but the distal are shorter and 

 sometimes bear a small terminal spine on the dorsal side. 



The radials are visible, but short. The IBr! are short, narrowing distally, not in 

 lateral contact. The IBr 2 (axillaries) are rhombic and broad. 



The 10 arms are about 100 mm. long, very slender, with a very uneven profile 

 from the base. The first brachials are short and not in contact. The second are 

 irregular in shape and about twice as long. The first two brachials each carry a small 

 lateral spine, that of the second lying closely beneath the base of the pinnule. The 

 first syzygial pah- (composed of the third and fourth brachials) is longer than the 

 second brachial. The brachials following to the seventh are about as long as broad 

 with strongly excavated surfaces. The second syzygial pair (composed of the ninth 

 and tenth brachials) is of the same length as the first. The three following brachials 

 are oblong, the form then becoming more trapezoidal, but never triangular. The 

 brachials broaden somewhat distally and their distal edges, which in the distal half of 

 the arms are somewhat spinous, strongly overlap the bases of those succeeding. At 

 their bases the arms are dorsally rounded, becoming more flattened distally. They 

 taper rapidly to about the fifteenth or twentieth brachial, more gradually from that 

 point onward. 



Syzygies occur between brachials 3+4, 9 + 10, 16 + 17, and distally at intervals of 

 3 or 4 muscular articulations. 



The disk is about 7 mm. in diameter and bears scattered calcareous nodules. 



PI is from 14 to 16 mm. long, flagellate and running out to a fine point, composed 

 of 35 to 44 short segments of which the distal bear a sort of terminal comb. P 2 is 

 similar, somewhat longer or of about the same length. P 3 is markedly shorter than 

 P 2 , composed of much fewer elongated segments and without a terminal comb. P 4 is 

 about as long as P 3 . The following pinnules very slowly decrease hi length. The 

 fourteenth pinnule is about 10 mm. long, and those in the distal half of the arms are 

 a few millimeters longer. 



Notes. In the detached arms from Albatross sta. 4621 the brachials are wedge- 

 shaped, all longer than broad, becoming elongate distally, with a finely serrate over- 

 lapping distal border which is more developed than in the specimens described. The 



556-622. 67 22 



