PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 531 



The 10 arms are nearly 40 mm. long. The first brachials are very short, deeply 

 incised by the posterior projection of the second ones, which are about as long as the 

 distal width. The first syzygial pair (composed of brachials 3 + 4) is slightly broader 

 than long. The next two brachials are rectangular, about twice as broad as long. 

 Those for some distance beyond are somewhat wedge-shaped and about as long as broad. 

 The distal brachials are elongated and slender, rectangvdar, with the articulations, 

 muscular and syzj-gial, slightly swollen. The distal edges of the brachials are everted 

 and produced into frills of toctlilike spines. Their entire surface, like that of the 

 ossicles of the IBr series, is very finely thorny. 



Syzygies occur between brachials 3+4, 9 + 10 (or exceptionally 8 + 9), 13+14 or 

 14 + 15, and distally at intervals of 2 to 4 (usually 3) muscular articulations. In the 

 two sjmtypes the widths at the first syzygy are 1.0 and 1.1 mm., the lengths from the 

 proximal edge of the IBr, to the first syzygy are 3.3 and 3.5 nun. and to the second 

 syzygy, 6.8 and 7.2 mm. 



Pi and Pa are absent. Pj is the first pinnule, and is a genital pinnule with a gonad. 

 There are two, three, or more, usually four, genital pinnules on each side of the arm. 

 The gonad on the outermost genital pinnule, more rarely that on P2, may be small. 

 None but the smaller outer genital pinnules have an ambulacra! furrow. The course 

 that the furrow would follow, if present, on the other genital pmnules is showm by a 

 double line of pigment. P2 is about 4 mm. long, with 8 segments. The fu-st segment 

 is slightly longer than broad, and the second is about half again as long as broad. The 

 third and fourth are about four times as long as broad. The distal segments, except 

 the terminal wliich is short and pointed, are as long, but more slender. The other 

 genital pinnules are similar but slightly longer, with more segments. P3 is more than 

 4 mm. long, ^\ith 9 segments. P4 is 5 mm. long, -with 9 segments. The distal pinnules 

 are 7 mm. long, ^vith about 15 segments, of which the fii'st is broader than long, the 

 second is about as long as broad, with the articulation between them greatly widened. 

 The other segments are about four times as long as broad, becoming slightly longer 

 and more slender distally. The articulations are swollen and the distal ends of the 

 segments are everted and spinous. 



On each genital pinnule there is a brood pouch that lies somewhat to the side of 

 the ovary and distal to it. The ovary hes on the tiiird and fourth segments of the 

 genital pinnules aiul, in dorsal v'iew, projects farther on the side away from the arm 

 from which the pinnule springs than on the other. The brood pouch hes along part 

 of the fourth, all of the fifth, and part of the sixth segments, and projects more on the 

 side toward the arm from which the pinnule springs than on the other. On some 

 pinnules the brood pouch is empty. Dr. John cleared and mounted two in which it 

 was not. In each there were two or three small eggs 0.10 mm. in diameter in the prox- 

 imal corner of the ovary. In one the remainder of the ovary appears to be occupied 

 by one enormous egg. In the other there are five large eggs of an irregular oval shape, 

 two about 0.25 mm. long, the other three much larger, the largest 0.62 mm. long by 

 0.36 mm. broad. The brood pouch of the first contains one large egg with no trace 

 of skeletal plates to be seen ^^^thin it; in the other there are two, the largest of which 

 is 0.67 mm. long by 0.51 mm. broad. 



On a P3 that Dr. John examined the ovary contained a small immber of large eggs 

 like those described and perhaps some small eggs. In the brood pouch there was one 

 yomig pentacrinoid about 1.3 mm. long, its crown consisting of two closed circles of 



556-622—67 35 



