414 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Diagnostic features. The outer cirrus segments have long, sharp, and prominent 

 dorsal spines; there are 16-24 arms 60-70 mm. long; and the cirri have 20 segments. 



Description. The centrodorsal is a convex disk. 



The cirri are about XV, about 20, up to 12 mm, in length, and slender. The fifth- 

 eighth segments are rather long (shown in the figure as about twice as long as broad) 

 and those following gradually become shorter, toward the end of the cirri being about 

 as long as broad. From the ninth onward the segments bear a sharp erect median 

 dorsal spine. In addition, each end of the midline of the dorsal surface is produced 

 into a spinelike process that lies parallel with the dorsal surface; of these horizontal 

 spinelike processes the distal is the larger and overlaps the proximal end of the 

 following segment. 



The radials are visible, and are partially united laterally. The IB^ are entirely 

 free laterally, and are somewhat shorter than the pentagonal axillaries. Of the five 

 postradial series, two have 2 divisions, one has 3, and two have only 1. The IIBr 

 and IIIBr series are 2. The IIBr! are only partially united with their neighbors. 

 The division series are widely separated laterally. Their lateral edges have no thick- 

 enings but are notched. There are no synarthrial tubercles. 



The 16 smooth and slender arms are 62.5 mm. long and are composed of rather 

 long brachials. The first brachials are somewhat longer exteriorly than interiorly 

 and are only partially united interiorly. The second brachials have approximately 

 the same form, with a slight posteriorly directed elevation of the middle of the prox- 

 imal border. The first syzygial pair (composed of brachials 3+4) is slightly longer 

 than broad. The next few brachials are discoidal, and those following are moderately 

 long, short wedge-shaped, distally becoming elongated. The syzygial pairs are long. 



Syzygies occur between brachials 3+4 and 16+17 (or hi arms arising directly 

 from the IBr axillaries between brachials 9+10), and distally at intervals of 5-8 

 muscular articulations. 



In arms arising from a IBr axillary the first two pairs of pinnules (Pi and P 

 and P 2 and P b ) are equally long and stout, 7 mm. in length. They are stiff and spine- 

 like and are composed of about eight segments, which with the exception of the two 

 basal and of the terminal are much longer than broad. The pinnules of the pair 

 following (P 3 and P e ) are of the same character but are only 4 mm. long, with five 

 segments. The pinnules of the next pair (P 4 and P d ) are the shortest, reaching only 

 3 mm. in length, and are less stiffened. The succeeding pinnules are very slender, 

 almost hairlike, and become about 7 mm. long. The lower pinnules of the other arms 

 differ in that they are a good deal longer on the outer than on the inner side of the 

 arms. 



The disk is 11 mm. in diameter and is only slightly incised. Sacculi are not 

 numerous but are deeply colored and conspicuous; they occur on the pinnules, on the 

 arms, and on the disk. 



The color is dorsally light yellowish white; the disk is light brownish gray with a 

 tinge of green. 



Notes. The specimen from Singapore has 24 arms 70 mm. long; the five post- 

 radial series bear 8, 2, 2, 7, and 5 arms; in the last one of the arms arises from the IBr 

 axillary, the other branch from the axillary consisting of one IIBr and two IIIBr 

 series, the latter bearing 4 arms. This specimen agrees very well with Hartlaub's 



