A MONOGRAPH OF THE EXISTING CRINOIDS 277 



are 16-18 mm. long with 40-45 segments. The pinnules of the first ten pairs are 

 without ambulacral grooves. 



4. The dorsal pole of the centrodorsal is 7 mm. in diameter. The cirri are 

 XXXVI, 37-40, from 35 to 42 mm. long. P, is 24 mm. long with 24-28 segments. 

 Pj is 27 mm. long with 33 segments. P3 is 22 mm. long with 28 segments. The 

 distal pinnules arc 15 ram. long with about 35 segments. On one arm there are syzy- 

 gies between brachials 3+4, 9+10, 18+19, 28 + 29, 36 + 37, 42 + 43, 48 + 49, 54 + 55, 

 59 + 60, 69 + 70, 77 + 78, 82 + 83, and 99 + 100. 



5. The dorsal pole of the centrodorsal is 9 mm. in diameter. The cirri are 



XXXIII, 36-41, from 30 to 40 nam. long. The arms are 120-180 mm. long. P, is 

 21 mm. long with 34 segments. P2 is 21 mm. long with 32 segments. The distal 

 pinnules are 14 mm. long with 35 segments. The pinnules of the first five to eight 

 pairs are without ambulacral grooves. The disk is 26 mm. in diameter. 



6. The dorsal pole of the centrodorsal is 6 nun. in diameter. The cirri are 



XXXIV, 38-40, about 40 mm. long. The arms are 150-220 mm. long. P, is 18 

 mm. long with 26 segments. P2 is 23 mm. long with 30 segments. P3 is 23 mm. 

 long with 33 segments. The distal pinnules are 12 mm. long with 33 segments. The 

 first eleven to sixteen pinnules are without ambulacral grooves. The disk is 25 mm. 

 in diameter. 



7. The dorsal pole of the centrodorsal is 7 mm. in diameter. The cirri are L, 

 33-38, from 35 to 45 mm. long. The arms are 180-240 mm. long. P, is 23 mm. 

 long with 35 segments. P2 has 25+ segments. P3 is 30 mm. long with 38 segments. 

 The distal pinnules are 18 mm. long with 37-40 segments. The first nine to eleven 

 pinnules are without ambulacral grooves. 



8. The centrodorsal is 12 mm. in diameter, with the dorsal pole 9 mm. across. 

 The cirri are XLII, 28-40, from 30 to 50 mm. long. Some of the cirri have a slight 

 opposing spine. The arms are 245-265 mm. long. Pi is 25-30 nmi. long with 33^2 

 segments. P2 is 25-30 mm. long with about 35 segments. The distal pinnules are 

 18 nun. long with 36 segments. The first eight pinnules are without an ambidacral 

 groove. The disk is 29 mm. in diameter. This specimen has two very large Myzos- 

 tomas in the pharynx. 



9. The dorsal pole of the centrodorsal is 7.5 mm. in diameter. The cirri are 

 XXXVI, 28-39, from 38 to 45 mm. long. The arms are 190-215 nmi. long. P, is 

 18 mm, long with 27 segments. P2 is 21 mm. long with about 30 segments. The 

 distal pinnules are 18 mm. long with 32 segments. The first nine to eleven pinnules 

 are without ambulacral furrows. The disk is 24 mm. in diameter. 



In a specimen from the Bonin Islands, as described by Gisl6n, the centrodorsal 

 is flattened with the free dorsal pole 2 mm. in diameter and marked with scars repre- 

 senting the obsolete sockets of discarded cirri. The cirri are XX, 25-29, from 18 to 

 24 mm. in length, and are arranged in two rows. The cirrus segments are uniform, 

 twice as broad as long, becoming half again as broad as long distally. The ante- 

 penultimate segment is as long as broad. The opposing spine is represented by an 

 indistinct prominence. The terminal claw is half again as long as the segment that 

 bears it, and is curved and pointed. One of the cirri is regenerated from the eleventh 

 segment. The radials are four times as broad as long, and are longest in the interra- 

 dial angles of the calyx. The IBr, are three times as broad as long and are free later- 



