A MONOGRAPH OF THE EXISTING CRINOIDS 67 



the median carination, the other branch running as a thickened rim along the distal 

 faces of the axillary, or as a ridge just within the distal edges, sometimes meeting just 

 proximal to (he distal apex, though usually forming a broad curve beyond which is the 

 apex. The IIBr series are 2. The, proximal and distal edges of the elements of the 

 IIBr series arc moderately thickened and everted; there is a slight rounded median 

 carination; the axillaries have thickened distal edges and produced proximal edges, the 

 latter running in a broad curve in the central part of the segment, in the lateral third 

 or fourth running nearly or quite straight to the lateral angle. 



The edges of the first two brachials are modified like those of the elements of the 

 IIBr series; there is a trace of a median carination. 



PI is 10-12 mm. long with 17-21 segments which, at first short, become about as 

 long as broad on the sixth, and nearly twice as long as broad terminally. The pinnule 

 is evenly tapering, rather strongly prismatic, and but little enlarged; the second-fifth 

 segments are sharp distally, though not distinctly cnrinate; the outer segments have the 

 distal angles rather prominent, though not produced. P 2 is 6.5 mm. long with 12 

 segments, shorter, more slender, and slightly less tapering than PI. The pinnule is 

 strongly and sharply prismatic, the profile of the prismatic angle on the outer segments 

 being slightly convex; the distal segments have slightly prominent distal angles. P 3 

 is 6 mm. long with 12 segments, similar to P 2 but tapering slightly more rapidly dis- 

 tally. The following pinnules resemble P 3 . The distal pinnules are slender, 9 mm. long 

 with 17 segments. 



Notes. The preceding description is based upon the specimen from Siboga station 

 302. Carpenter's original description, based upon two specimens from Challenger 

 station 192 and one from Challenger station 201 (the last representing P. granulata) was 

 as follows: 



The centrodorsal is a thick convex plate with the dorsal pole free. 



The cirri are XV-XX, about 20; a few of the segments are longer than wide, and 

 the latter are somewhat compressed laterally, with blunt dorsal spines. 



The radials, and sometimes parts of the IBr,, are concealed. The IBrj are short 

 and sharply convex with a slight median ridge, and they meet one another laterally 

 beyond the angles of the centrodorsal. The IBr 2 (axillaries) are short and widely 

 rhombic, also with a median ridge, and forming a small tubercle with the preceding 

 ossicles. The IIBr series are 2, with a faint median ridge; the axillaries are short and 

 widely rhombic. The outer sides of the IBr axillaries, the elements of the IIBr series, 

 and the first two brachials are slightly flattened, and the inner sides of the second 

 brachials and the first syzygial pairs arc also somewhat flattened. 



The 15-20 arms arc 140 mm. long and are composed of 150 or more brachiids, 

 of which the lowest are nearly oblong with indications of a dorsal keel and raised distal 

 edges, and those following arc more triangular and distinctly carinate, gradually be- 

 coming quadrate and somewhat compressed laterally, with a tendency to overlap. 



Syzygies occur between brachials 3 + 4, again from between brachials 12+13 

 to between brachials 13+14, and distally at intervals of from 3 to 8 (usually 5 or 6) 

 muscular articulations. 



P 1 is about 10 mm. long with about 18 short segments, the first few of which are 

 much wider than their successors and slightly prismatic. P a is smaller, with the I >a ;.! 

 segments more rounded and not so wide. The following pinnules diminish in size to 



