286 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



and keeled; they strongly overlap the bases of the succeeding segments so that here 

 the dorsal profile of the cirri appears serrate; the outermost segments have small 

 dorsal spines. 



The radials are only partially visible. The IBr, are partially united laterally. 

 The IBr 2 (axillaries) are rather short and pentagonal. One of the IBr series bears 

 two undivided arms. The four others bear on one side an undivided arm and on the 

 other a IIBr 4(3+4) series. Each IIBr series bears a single IIIBr 2 series. The 

 first elements of the IIBr series are short and of the same length as the first brachials 

 of the adjacent arms with which they are laterally united. 



The 18 slender and rather smooth arms are apparently about 65 mm. long. 

 The basal brachials are short, the first being shorter than the second. The first 

 syzygial pair (composed of brachials 3+4) is also short. The following brachials are 

 short disks with feebly produced ends. From the eighth or ninth brachial onward 

 there is a series of brachials that are triangular and a good deal larger; about the 

 thirtieth the brachials become shorter and blunter, wedge-shaped, farther on short 

 disco idal, and finally more squarish. 



Syzygies occur between brachials 3+4, again from between brachials 11 + 12 to 

 between brachials 14 + 15, and distaUy at intervals of from 9 to 11 muscular articula- 

 tions. The second syzygy in arms which arise from the IBr axillaries is between 

 brachials 8+9 or 9 + 10, and the intersyzygial interval beyond is 5 or 6 muscular 

 articulations. 



The lowest pinnules, whether on the IIBr series or on the arms, are very small 

 and delicate with carinate and rather large basal segments. P t when following a 

 pinnule on a IIBr series is a good deal larger than these and measures about 9 mm. 

 in length. P a is very small. The largest pinnule is P 2 , which measures 12 mm. 

 The pinnules following decrease in length to P 8 . The pinnule of the sixth brachial 

 (P b ) is smaller than that of the fifth (P z ). The pinnule of the seventh brachial (P 3 ) 

 on arms arising directly from a IBr axillary is almost as long as that of the fifth (P 2 ). 

 The pinnules of about the first 20 brachials have a few carinate basal segments. The 

 length of the succeeding pinnules reaches 7 mm. 



The disk is 13 mm. in diameter, and is naked and incised. Sacculi are very 

 numerous on the arms and pinnules. 



The color is light chocolate-brown, with the disk dark brown. 

 The preceding description is adapted from Hartlaub's description of the type 

 specimen. 



Notes. One of the specimens from off Jolo has 18 arms about 120 mm. long. 

 The other is very smell with 11 arms, one IIBr 4(3+4) series being developed. 



The specimen from Siboga station 99 has 15 arms about 70 mm. long; each IBr 

 series bears on the right hand side (as viewed dorsally) a IIBr 4(3+4) series; the two 

 additional arms on the left anterior ray are as yet only 22 mm. in length, measured 

 from the axillary. The longest cirrus has 29 segments. This appears to be a young 

 individual just completing the adolescent autotomy. 



Of the specimens from Singapore one has 16 arms 50 mm. long and another has 15 

 arms 55 mm. long. 



Localities Dr. Th. Mortensen's Pacific Expedition 1914-'16; off Jolo, Philip- 

 pines; about 36-55 meters; sand and coral; March 19, 1914 (2). 



