774 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



long and the wadth at the joint between tliem is 2.1 mm. The width at the first sj-zygy, 

 between brachials 4 + 5, is 2.7 mm. so the two basal segments are distinctly constricted. 

 The length fi'oni the proximal edge of the first brachial to the first syzygy is 6 mm. The 

 only portion of arm remaining attached beyond the first syzygy is broken at the second 

 one, which is at 11 + 12, though a detached portion, probably from the fifth brachial on, 

 has the next syzygj'- at 10 + 11. 



The first four brachials are rectangular in shape but after the first syzjgy they 

 become more wedge-shaped and the distal ones are triangular, becoming longer than 

 broad. The syzygies are very variable in position. On the middle part of the arms 

 they are usually separated by 4 to 6 muscular articulations but further out the interval 

 may be as many as 12 or 13. There are moderate-sized articular tubercles on alternate 

 sides as far as the second S3'zygy, after which they are reduced. 



The pinnules arc all broken. A major part of a proximal one attached to a piece 

 of the disk measm-es 10 mm. in length and has 18 segments, none of which is longer 

 than broad. A pinnide from the middle of the arm, of which only about half remains, 

 has the slightly flared segments much more elongated, the second one being almost 

 twice as long as wide though the first is still short. The genital pinnules appear to 

 extend quite far out on the arms as two are preserved on a section where the width 

 at a sj'zygy is only 1.6 mm. They have the first two segments short but the third and 

 those following are about half again as long as broad. The first pinnule arises from 

 the second brachial on the right side in sLx cases and from the left in the other four. 



No estimate can be made of the total length of the arms since none of the frag- 

 ments remaining is longer than 40 mm. 



Notes. — In the specimen taken by the Siboga the centrodorsal is 2.5 mm. high and 

 5.5 mm. in diameter; the very flattened dorsal pole is 2.5 mm. across. Around the 

 sides there are about forty cirrus sockets in three crowded rows, which show a tendency 

 towards arrangement in vertical lines. The cirri are all broken ofi: short. The third 

 segment is about two and a quarter times as long as broad. 



The 10 radials are in mutual apposition aU around the calyx, being only slightly 

 separated at the distal angles. They are short, projecting beyond the centrodorsal 

 for a distance equal to from a third to a half the length of the first brachials. 



The first brachials are approximately oblong, averaging twice as broad as long. 

 The second brachials are similar, of about the same size or slightly shorter. The arm 

 measures 6 mm. from the distal edge of the radials to the distal edge of the foiu'th 

 brachial (the first syzygy) and the wudth of the first syzygy is 2.4 mm. 



Gisl6n (1928) gave some brief notes on the type specimen including the fact that 

 there arc 23 septa on the syzygial face of the foiu-th brachial, of which 13 are complete. 



Localities. — Challenger station 214; off the Meangis Islands (lat. 4°33' N., long. 

 127°06' E.); 914 meters; temperature 5.44° C; blue mud; February 10, 1875 [P. H. 

 Carpenter, 1879, 1888; A. H. Clark, 1913] (1, B.M.). Type locality. 



Siboga station 122; Sangi Islands, northeast of Celebes (lat. 1°58'30" N., long. 

 125°00'30" E.); 1165-1264 meters; bottom, stone; July 17, 1899 [A. H. Clark, 1918] 

 (1, Amsterdam Mus.). 



Bemarks [by A.M.C.]. — The key to the species of Thaumatocrinus left by Mr. 

 Clark distinguished T. naresi and rugosus from the Japanese borealis by the appreciably 

 longer second brachials (compared with the fii-st) in borealis alone. In measuring the 

 type specimen of naresi, I found that the lengths of the first two brachials on each arm 



