A MONOGRAPH OF THE EXISTING CRINOIDS 99 



and later less obliquely wedge-shaped and as broad as long. The distal portion of the 

 arms is missing. 



Syzygies occur between brachials 3 + 4, 9 + 10 (or 10 + 11), 14+15, and distally 

 at intervals of from 3 to 6 (usually 5) muscular articulations. 



Pi is 6 mm. long with 9+ segments, stout, and tapering evenly to the tip. The 

 first segment is about twice as broad as the median length, with the proximal border 

 roundedly angulate. The second segment is about one-third again as long as broad. 

 The third segment is twice as long as the median width, slightly narrower distally 

 than proximally, and very slightly constricted centrally. The following segments 

 are mostly about three times as long as broad, becoming somewhat longer toward 

 the end of the pinnule. The first, second, and third segments are distinctly, though 

 bluntly, carinate on the side toward the arm tip, this carination dying away on the 

 fourth. The segments in the outer portion of the pinnule have the distal edge on 

 the side toward the arm tip slightly everted and coarsely dentate. P2 is stouter 

 basally than Pi and tapers more gradually. It is of the same character as Pi, differing 

 only in its superior size and greater length, being apparently about 3 mm. longer. 

 The first two segments are rather sharply carinate, and the third and following have 

 the distal edge abruptly everted and serrate. P3 is smaller, shorter, and somewhat 

 less stout than P2, and is composed of 12 segments. It is of the same width basally 

 as Pi and appears to be of about the same length or slightly longer. Its component 

 segments are slightly shorter than those of Pi, and it is somewhat less rigid. P4 is 

 scarcely more than half as long as P3 and is composed of 10 segments. It is about 

 half as broad as P3 at the base and tapers rapidly to the tip. The segments are 

 proportionately shorter than are those of P3, becoming about as long as broad on the 

 fourth and about twice as long as broad terminally. Ps and the following pinnules 

 are somewhat shorter than P4, and are more slender and flexible. 



Notes.— The preceding description was drawn up from one of the specimens from 

 Magneta station XIX, which was very kindly lent me for study by Dr. Hubert 

 Lyman Clark. 



Dr. Clark's original description, based upon specimens from Alaer, is as follows: 

 The centrodorsal is moderately large, but notably thick, about 5 mm. in diameter, 

 with the bare dorsal area about 2 mm. across and minutely tuberculated. 



The cirri are XXI-XXIII, 15-17, relatively long (9 or 10 mm.) and stout. The 

 transverse ridges on the distal segments are minute or wanting, but the opposing 

 claw is marked. None of the segments are obviously longer than broad. 



The elements of the IBr series and the first two brachials have well-marked 

 ventrolateral processes. 



There are 10 arms which are composed of 80 brachials. The first half-dozen 

 brachials are more or less quadrate, and those succeeding are wedge-shaped with 

 flaring and slightly overlapping distal ends, becoming quadrate and longer than broad 

 at the arm tip. 



Syzygies occur between brachials 3+4, 9 + 10, and distally at intervals of 6-8 

 muscular articulations. 



All the pinnules are more or less cyhndrical. Pi is about 7 or 8 mm. long, of 10 

 or 11 segments, and moderately stiff. Pa is similar, but often distinctly larger. Pj 

 and Pb are about equal, distinctly the largest and most spikclike of the pinnules, of 



