486 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



tapering distally. The first 2 brachials are similar, slightly wedge-shaped, about 

 twice as broad as long; the first are united interiorly, but the second are entirely 

 free interiorly. The first syzygial pair (composed of brachials 3 + 4) is oblong, 

 usually about twice as broad as long. The next 2 brachials are oblong, two or three 

 times as broad as long, and those following become triangular, about half again as 

 broad as long, about the middle of the arm becoming wedge-shaped, twice as broad 

 as long, or, in some specimens, very short wedge-shaped. The division series are 

 smooth; but the brachials from the fifth onward have more or less, often very strongly, 

 overlapping distal ends which are armed with minute spines. 



One or two of the posterior postradial series are sometimes smaller than the 

 others, with ungrooved arms and no ambulacral grooves running to them from the 

 disk. 



Syzygies occur between brachials 3 + 4, again from between brachials 12 + 13 to 

 between brachials 19 + 20 (usually in the vicinity of the thirteenth or fifteenth bra- 

 chials), and distally at intervals of 4 or 5 muscular articulations. 



The disk is 30 mm. in diameter, naked or with scattered concretions in the anal 

 area. The mouth is marginal, radial, or interradial. The anal area is large and the 

 anal tube is central. 



P D is from 18 to 20 mm. in length, rather slender, scarcely, if at all, larger than 

 the following pinnules. It is composed of about 40 segments, usually all slightly 

 broader than long. The terminal comb consists of 9-11 small rounded triangular 

 teeth, all, or nearly all, of which are repeated in miniature on the inner side of the 

 segments. The next pinnule ordinarily is on the outermost division series; it is from 

 14 to 18 mm. long and resembles P D , being very slightly, if at all, more slender. PI is 

 12 mm. long, as stout basally as the preceding pinnule, but tapering somewhat more 

 rapidly because of its lesser length. P 2 is 9 mm. long, about as stout basally as PI, 

 but tapering rapidly. It is composed of about 22 segments, which at first are twice 

 as broad as long, becoming about as long as broad on about the sixth. The following 

 pinnules are similar, very slightly stouter basally and not tapering so rapidly, about 

 8 mm. long; their segments have prominent and slightly overlapping finely spinous 

 distal ends. Distally the pinnules gradually become moderately slender, 7 or 8 mm. 

 in length, with 15-18 segments, most of which are about as long as broad. 



The color in alcohol is brownish yellow, a line from the angles of the centrodorsal 

 to the perisome at the interradial angles of the calyx continuing in a lateral line along 

 the division series and arms dark yellowish or reddish brown, the pinnules greenish 

 yellow and the perisome brown ; or bright green ; or bright yellow, darker ventrally ; 

 or plain reddish, yellowish, or purplish brown, darker on the ventral surface; or dark 

 reddish brown, with the pinnules and ventral surface evenly and finely marbled with 

 green and reddish brown in about equal proportions. 



Notes, The specimen from Siboga station 99 has 85 arms which are 130 mm. in 

 length. 



Mortensen's specimen from a coral reef off Jolo seems to be referable to this 

 species rather than to C. rotula. It has 45 arms. There are 7 IIBr 4 (3 + 4) series, all 

 followed by IIIBr 2 series, and 3 IIBr 2 series, all of which are followed by IIIBr 



