J54 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



series Pi is 6^'inm. long with 14 segments. Pj is 9.5 mm. long with 17 or 18 segments. 

 P3 is 7-8 mm. long with 16-18 segments. The distal segments of P2 and P3 are very 

 long, three times as long as broad, and their distal ends are serrate. P. is lacking. 

 Pb resembles Pj. Pi is usually absent on the inner arm of a IIIBr series. The distal 

 pinnules are 7 mm. long with about 20 segments. The disk is very deeply incised, 

 with the smallest diameter 4 mm. and the largest 10 mm. The color is red-violet with 

 yellow longitudinal bands, distally with yellow and red spots mingled. 



In another specimen from Bock's station 59 the bare dorsal pole of .^the centro- 

 dorsal is 2 mm. in diameter. The cirri are XXV, 25-31, from 15 to 20 mm. long. 

 Usually a single dorsal spine is developed from the sixteenth segment onward. The 

 middle prominence is larger on the proximal segments. The radials project beyond 

 the rim of the centrodorsal in the interradial angles of the calyx. The IBri are four 

 times as broad as long. The division series are of rather uniform thickness. The 

 IIBr and IIIBr series are 2. There are 16 arms — possibly 2 more — all broken. P, is 

 from 5.5 to 6 mm. long with 14-16 segments, and is absent from the inner arms arising 

 from IIIBr axUlaries. AU the brachials beyond the third are broken. The disk has 

 been thrown off. The color is light brown. 



Of the specimens from Albatross station 5213 the largest have the arms 95 mm. 



long. Ten have 11 arms, eight have 12 arms, six have 13 arms, four have 14 arms, 



three have 15 arms, two have 16 arms, three have 17 arms, two have 19 arms, and 



four have 20 arms. One is badly broken, and there are two 10-armed young. 



The specimens from Albatross station 5212 have 16, 18, and 20 arms. 



The six specimens and one fragment secured by the Challenger on the reefs at 



Cebu were regarded by Dr. P. H. Carpenter as representing a new species which he 



called Antedon disciformis and described as follows. The centrodorsal is a thick 



pentagonal disk with an irregular row of marginal cii-ri and the dorsal surface free. 



The cirri are XV-XX, 25-30. Several of the segments are longer than broad. The 



fourth or fifth segments project beyond their successors on the dorsal side, and those 



following gradually develop a sharp forward-projecting spine at their distal edge. As 



the segments shorten distally this comes to be placed farther and farther back, and is 



both shorter and more upright. The radials are mostly concealed. The IBri are 



oblong, and are quite free laterally. The IBr2 (axillaries) are pentagonal, nearly twice 



as long as the IBrj. The postradial series are well separated and may divide twice. 



The IIBr series arc 2. The IIBri are nearly oblong. The 15-20 arms are probably 



about 75 mm. long and consist of about 120 smooth and rounded brachials of which 



the first few are discoidal and their successors triangular, about as broad as long, 



gradually becoming more quadrate. The first syzygy is between brachials 3+4, the 



second is from between brachials 9+10 to between brachials 15 + 16, and the distal 



intersyzygial interval is from 2 to 6 muscular articulations. Pi is composed of about 



18 short segments which are but little longer than broad. P» is absent. The pinnules 



of the next pair (P2 and Pt) are rather stouter and much longer than Pj, reaching 12 



mm. in length and consisting of 20 elongated segments the apposed edges of which are 



somewhat produced toward the ventral side. P3 may be nearly equal in size to Pj or 



it may be distinctly smaller, and its successors diminish in length to about P5, and then 



increase, becoming exceedingly slender in the outer parts of the arms. The disk is 



about 8 mm. in diameter and is naked and rather incised, with a few sacculi, which 



