PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 333 



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 4 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 

 angles to the axis of the arm, forming (as viewed along the arm) a high rounded-trian- 

 gular coarsely spinous process. Shortly after the second syzygy the brachials become 

 very obliquely wedge-shaped with strongly concave ends, not quite so long as broad, 

 with the distal border rather strongly but evenly produced and coarsely spinous. 

 Distally the brachials become gradually less and less obliquely wedge-shaped, and 

 toward the end of the arms somewhat longer than broad and slightly constricted ba- 

 sally. The coarsely spinous production of the distal edge is conspicuous to the arm 

 tips. 



Syzygies occur between brachials 3+4, 9 + 10 and 14 + 15, and distally at intervals 

 of 3 muscular articulations. 



PI is 10 mm. long, very slender, flexible and flagellate, and is composed of 36 

 segments of which the first is between 2 and 3 times as broad as long, those succeeding 

 gradually increasing in length and becoming about as long as broad on the eighth and 

 very slightly longer than broad on the thirteenth to fifteenth, the remainder being 

 about as long as broad. The third to fifth segments have the outer edge (the edge 

 toward the arm tip) somewhat swollen and produced into a roundedly angular blunt- 

 edged process which on the next two segments is truncated and lower. The last 18 

 segments have the side toward the arm tip with a prominent rounded process which is 

 minutely spinous on the crest, the distal profile of this portion of the pinnule being 

 prominently scalloped as in Anthometra adriani. On the 6 or 8 segments preceding 

 these, going toward the base of the pinnule, the swelling of the edge of the segments 

 becomes more and more restricted to the distal end, and also progressively lower, 

 finally disappearing altogether. 



P 2 is of about the same length as PI, but it is considerably stouter basally, some- 

 what less flexible, and is composed of only 30 segments. The first segment is twice as 

 broad as long, trapezoidal, the second is longer with the proximal angles broadly trun- 

 cated, the third is about as long as broad, and the ninth and following are about twice 

 as long as the width of their proximal ends. Distally the segments become shorter 

 again, the last 4 or 5 being about as long as their greatest width. On the tenth seg- 

 ment the median portion of the distal border of the side toward the arm tip becomes 

 swollen and minutely spinous. On the succeeding segments this swelling rises in 

 height and extends basally so that the end of each segment on the side toward the arm 

 tip projects some distance beyond the base of the following segment, the dorsal profile 

 running in a straight line from the apex of this production to the base of the segment. 

 Gradually the maximum height of this projection moves basally, and on the last 4 or 

 5 segments it is about in the middle, so that the segments' are seen to be provided, on 

 the side toward the arm tip, with a conspicuous, evenly rounded, finely spinous, blunt- 

 edged crest. 



P 3 is 8 mm. long with 16 segments, somewhat stouter basally than P 2 , less flexible, 

 and tapering evenly from the base to the tip. The first segment is about 3 times as 



