120 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Arms 19 (in the type), about 90 mm. long. The first two brachials are similar, 

 rather small, wedge-shaped, about twice as broad as long exteriorly, the first united 

 interiorly in the proximal half, diverging widely in the distal. The third to the 

 seventh or eighth brachials are oblong or slightly wedge-shaped, about twice as 

 broad as long, the following becoming triangular, about as broad as long, and in the 

 distal portion of the arm wedge-shaped again and longer than broad, reaching a 

 length of about twice the breadth in the terminal portion. 



The first syzygy is between brachials 1 + 2 except on arms arising direct from a 

 IBr axillary and on the exterior arms of each ray where it is between brachials 3 + 4; 

 on the interior arms a syzygy between brachials 1 + 2 is often immediately followed 

 by another between brachials 3+4. The distal intersyzygial interval is from 3 to 5 

 muscular articulations. 



P! is long and slender, slightly stouter basally than P 2 , 15 mm. long, with about 

 40 segments, of which the first is very short, the next 8 or 10 are about as long as 

 broad, the following are about half again as long as broad, and the distal are again 

 about as long as broad. The terminal comb begins abruptly, and is composed of 

 about 12 large, long, bluntly triangular teeth, which are rather strongly incurved, 

 and about as long as the lateral diameter of the segments which bear them. The 

 series of tooth-bearing segments maintains the same general direction as the seg- 

 ments preceding. P 2 is similar but shorter, about 11 mm. long. P 3 is similar but 

 shorter, 8 mm. long with 26 segments; its comb is similar to that of P! and P 2 . P 4 

 and P 6 are similar to P 3 . P 6 is similar to P 5 , with a similar comb, but stouter basally 

 and bearing a small gonad on the third-fifth segments. The following pinnules are 

 stouter throughout, but of the same length, composed of squarish segments, and 

 without combs. The distal pinnules are slender, about 11 mm. long. 



The mouth is central; the anal tube is small and inconspicuous, the anal area 

 being no larger than the other interambulacral areas. Two of the ambulacral 

 grooves divide at the mouth, as in Thaumatocrinus, but in one of these the two 

 branches join again just before branching to the arms, forming a sort of perisomic 

 island. 



Notes. As described by Gislen, the specimen from Mortensen's station 9 has 

 the centrodorsal flattened, 3.8 mm. in diameter, with the cirri arranged in 2 rows. 



The cirri are XXXVI, 13-15, from 14 to 17 mm. in length. The longest cirrus 

 segment, which is the fifth or sixth, is three times as long as broad. From the eighth 

 onward a dorsal spine is developed. 



The 19 arms are 105 mm. long. Of the IIBr series, 7 are 2 and 1 is 4 (3 + 4). 

 There is a single IIIBr 2 series. On the two arms following the IIBr 4 (3 + 4) series there 

 is a pinnule on the first brachial and a syzygy between brachials 2 + 3 as in Capillaster. 



Gislen gives an example of the usual arm structure. In this the IBr 2 series 

 bears 2 IIBr 2 series. In the 2 arms borne by the IIBr series to the left there are 

 syzygies between brachials 1+2, 3+4, 15 + 16, and 19 + 20 or 20 + 21. On the 

 inner arm borne by the IIBr series to the right there are syzygies between brachials 

 1+2, 13 + 14, and 17 + 18, while on the outer arm borne by the IIBr series to the 

 right the only syzygies given are between brachials 14 + 15 and 19 + 20. 





