A MONOGRAPH OF THE EXISTING CRINOIDS 219 



united laterally, and slightly raised in the middle of their junction with the axillaries. 

 The IBr 2 (axillaries) are half again as long as the IBr : , widely pentagonal, with open 

 distal angles, and also slightly raised in the middle of the proximal edge. The 30 

 armsare 100 mm. long and are composed of 150+ brachials. The postradial series may 

 divide three times. The IIBr series are 4 (3 +4) , and the IIIBr series are 2. The first 

 ossicles following each axillary are rhomboidal and are closely united laterally, with 

 the distal edge very shghtly incised to receive the convex hinder edge of the following 

 ossicle. The first syzygial pair, composed of brachials 3+4, is short and oblong. 

 The next four or five brachials are also short with somewhat oblique terminal faces 

 and slight backward projections alternately on the inner and outer sides. The fourth 

 and sixth brachials are thus longer on their inner sides, and the fifth and seventh on 

 their outer ones. The following brachials are short, bluntly wedge-shaped, and 

 overlapping, nearly twice as broad as long, becoming more oblong about the middle 

 of the arm. The first syzygy is between brachials 3 +4, and the next is from between 

 brachials 9 + 10 to between brachials 17 + 18, usually between brachials 13 + 14; there 

 is then an interval of 8-15 (usually 10 or 11) muscular articulations between the 

 syzygies. 



P D is quite small, little more than half as long as, and far more slender than, 

 those on the second and third brachials, which are about equal. The next pair are 

 still larger, and the third pair (on the sixth and seventh brachials) still more so, 

 consisting of about 35 stout segments and reaching nearly 35 mm. in length. That 

 on the seventh brachial is rather the smaller, and the next pair is considerably smaller, 

 only about equal to the first pair. The diminution continues to about the seventh 

 pair, which are not especially small, being scarcely less than 10 mm. long. The re- 

 maining pinnules are of about the same length, but gradually become slenderer. 

 The basal segments of the lower pinnules from P D onward have rather sharp dorsal 

 keels. These may be less marked on the stout segments of the pinnules of the second 

 and third pairs, but reappear on the second and four following segments in the fourth 

 pair, and then gradually decrease in distinctness, disappearing altogether by about the 

 twenty-fifth segment. The disk is naked and considerably incised and is 15 mm. in 

 diameter. Sacculi are closely set along the pinnule ambulacra. The color in alcohol 

 is light brown. 



The other specimen from Hongkong was described by Carpenter as Antedon 

 bipartipinna in the following terms. The centrodorsal is a thick slightly convex 

 disk bearing a single row of cirri. The cirri are XIV, with nearly 60 segments and 

 may reach almost 60 mm. in lengtb. They are long and stout. The basal segments 

 are very broad, nearly 2 mm. in width, the fifteenth and following are about as long 

 as broad, and the terminal are slightly longer than broad, quite smooth dorsally. 

 The terminal claw is very imperfectly formed and there is no trace of an opposing 

 spine. The radials are partially visible at the angles of the calyx. The IBr, are 

 shorter in the middle line than laterally, where they are closely united to their fellows. 

 The IBr, and the short, almost triangular, axillaries rise to a slight tubercular eleva- 

 tion in the middle line of their junction. The IIBr series are 4(3+4). The IIIBr 

 series are usually 4(3+4) but sometimes 2. The first ossicles after each axillary are 

 rhomboidal and closely united laterally, and the second are more wedge-shaped. The 

 middle of the articulation between the first two ossicles is tubercular, as in the case 



