PART 5 



A MONOGRAPH OF THE EXISTING CRINOIDS 



329 



than long; its interior edge is longer than the exterior. The brachials between the 

 first and third syzygy are slightly wider than long; in each, one side, alternately the 

 exterior and interior in successive brachials, is longer than the other. Immediately 

 beyond the third syzygy the brachials are triangular and more elongate. The distal 

 edges of all but the most proximal brachials are everted and finely spinous. 



P! is of about 30 to 33 segments and 7 mm. long. None of the segments except 

 for three or four in the region of the fifth is longer than broad. The dorsal edges of 

 the proximal segments are raised into roughened protuberances, those of the middle 

 segments into short spiny crests, while those of the distal segments are still more 

 strongly produced so as to give the appearance of a rudimentary terminal comb. When 

 examined under the microscope the comblike structure is seen to be of less dense 

 stereom than the core of the segments. No other pinnule has this structure. 



P 2 is a genital pinnule of 21 to 23 regular, cylindrical segments; it is about 8 mm. 

 long, that is longer, although of fewer segments, than P!. It bears a small gonad on 

 the fourth to sixth segments. The first two segments are short, the third about as 

 long as broad. The fourth is longer than broad. The remaining segments are about 

 three times as long as broad with swollen and spinous distal ends. P 2 lacks an ambu- 

 lacral furrow it first appears on P 6 . 



There is no complete PS. P c is of more than 16 segments, all but the first three of 

 which are elongated; it is about 9 mm. long. A long gonad lies on the fourth to seventh 

 segments. P, is of 16 segments, 9 mm. long, with a gonad along the third to eighth 

 segments. 



Sacculi of a bright yellow color and somewhat irregularly arranged are abundant 

 along the pinnule ambulacra; they occur too on the lower genital pinnules which lack 



a 



FIGURE 17. Floromctra goughi John, B.M., 19S8.S. 2.26-28, Discovery Investigations station 

 2493: a, Centrodorsal; b, division series and first two brachials; c, tip of P,; d, tip of cirrus. 



