A MONOGRAPH OF THE EXISTING CRINOIDS 451 



pinnules. On the remaining postradial series the rigiit arms are usually a little 

 shorter than the left. On one postradial series both arms have 15 brachials; one has 

 syzygies between brachials 3 + 4 and 12 + 13, the other only a single syzygy, between 

 brachials 3+4. P3 is 2 mm. long with 12 segments. 



In a specimen from Bock's station 56 the centrodorsal is sharply conical, 3 mm. 

 broad at the base and 3 mm. high, with the dorsal pole smooth and arched and some- 

 what hollowed at the summit. The cirrus sockets are arranged in 10 columns which 

 are separated by midradial interspaces. The cirri are XVII, 80-81, 50-55 mm. long. 

 The first and second segments are short, those foUowuig increasing to about as long 

 as broad or a little longer on the fifth-twentieth segments, then decreasing so that 

 those from about the fortieth onward are about twice as broad as long. Usually 

 the segments from the third (or fifth) to about the fifteenth have a doi-sal crest which 

 is most marked on the pro.ximal segments. The fifteenth-twenty-fifth segments are 

 most often more or less smooth, then a dorsal carination appears which distally be- 

 comes accentuated into a dorsal spine. The opposing spine is larger than the spines 

 on the segments preceding, rising to a height equal to half the width of the penultimate 

 segment. From three to five of the terminal segments have verj^ slight dorsal spines, 

 or even lack them entirely. The terminal claw is short, equal in length to the pen- 

 ultimate segment. The radials are four times as broad as long, with a median tubercle. 

 The IBr^ are two and one-half times as long as broad, and are laterally united basally. 

 The IBr2 (axillaries) are low pentagonal and, like the IBri, have an indistinct median 

 longitudinal crest. The IIBr series are 2, resembling the IBr series. The 16 arms are 

 65 mm. long. The first brachials are interiorly united. The arms are sharply 

 flattened laterally as far as about the tenth brachial. After the tenth the brachials 

 become decidedly triangular. From the fortieth to the fiftieth onward the brachials 

 have a median distally directed spine. The last ten brachials have only rudimentary 

 pinnules. On two sample arms syzygies occur between brachials 3+4, 12 + 13, 

 22 + 23, 30+31, 37 + 38; and brachials 3+4, 13 + 14, 21+22, 28 + 29, 35+36, 41+42, 

 48+49, 55 + 56. In a single case the first two syzygies are between brachials 4 + 5 

 and 13 + 14. The distal intereyzygial interval is 6-9 muscular articulations. Pi is 

 5 mm. long, smooth and prismatic, with 12 segments of which the first is broader than 

 long and those following are from half again to twice as long as broad. P2 is 5.5 mm. 

 long with 12 segments. P3 is 6 mm. long with 12 segments. Pio is 8 nun. long with 

 15 segments. The distal pinnules are 10 mm. long with IS segments which are twice 

 as long as broad. The disk is 8.5 mm. in diameter. The color in alcohol is yellow- 

 brown, in life probably flame-color as the alcohol and still more the formalin in which 

 the other specimens are preserved is stained bright red. 



In another specimen from station 56 the ccntrodoi-sal is 4 mm. broad at the base 

 and 4 mm. high; the dorsal depression is only slightly developed. The cirri are XX, 

 85-90, 60-70 mm. long. There is no distinct dorsal spine on the cirri before the twen- 

 tieth or twenty-fifth segment. The sixth-twelfth segments have a slightly indicated 

 dorsal crest. The 12 arms are 90-100 mm. long. On a sample postradial series with 

 three arms the syzygies are distributed as follows. On the undivided arm, between 

 brachials 3+4, 10+11, 17 + 18, 25 + 26, 32 + 33, 38 + 39, 43 + 44, 48+49. On the 

 inner arm from the llBr a.xillary, between brachials 1+2, 3+4, 9 + 10, 15+16, 20 + 21, 

 28+29, 34 + 35, 40 + 41, 45 + 46; on the outer arm from the IIBr axillary, between 



