222 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



The radials are wholly concealed. The IBr! and the pentagonal IBr 2 (axillaries) 

 are very short and not in lateral contact. The IIBr series are 4 (3 + 4), and the 

 IIIBr series are 3 (2 + 3), mostly internally developed. The division series have a 

 smooth rounded surface and only very slightly projecting sides. 



The arms are nearly 30 in number; one ray is broken off and lost; on the other 

 4 the arms total 23. The arms, which are all broken, increase very slightly in width 

 from the base. 



The first arm syzygy is between brachials 2 + 3, rarely between brachials 3 + 4, 

 and the second is usually between brachials 8 + 9; the distal intersyzygial interval is 

 from 3 to 5, usually 4, muscular articulations. 



P D is about 16 mm. long, flagellate, composed of 37 segments. A few of the 

 basal segments are stout. The first 3 are incorporated in the perisomic plating of 

 the interradial areas of the disk. The pinnule tapers very rapidly in the proximal 

 half. The distal edges of the segments are strongly produced and spiny. The comb 

 is very poorly developed and does not extend on to the terminal segments. While 

 the basal segments are broad, those in the distal half of the pinnule are elongate 

 cylindrical. There is no carination of the basal segments, although the second 

 segment bears a sharpened edge, indicating an incipient carination. On P P or P 1( 

 however, there is a strong carination of the first, second, and third segments. These 

 pinnules are markedly weaker than P D , although their length is only slightly less; 

 they are composed of about 33 segments. The comb is very poorly developed and 

 extends over about 6 segments; the terminal segments are not included. The next 

 pinnule is again markedly weaker than those preceding, becoming slender and 

 flagellate beyond the sixth or seventh segment; it is composed of about 20 segments, 

 and there is only a trace of a comb. The difference in size between the basal seg- 

 ments and those following is much less than in PI, and in the pinnule next beyond 

 this difference is no longer to be seen. This last is shorter, about 5 mm. long, with 

 10 segments, of which the outer bear a comb of 5 or 6 teeth. From this point the 

 length of the pinnules gradually increases, so that the pinnule on the tenth bracbial 

 is 6 mm. long. Except for the few basal segments of the first 2 pinnules, the pinnules 

 are very slender. 



The dorsal iiiterradial perisome is plated. 



In the specimen from Blake station 171, as described by Hartlaub, the centro- 

 dorsal is thick, discoidal, with the dorsal pole flat. 



The cirri are about XL, about 16, and are arranged in several rows. The first 

 2 segments are short and the following to the eighth are much elongated, those 

 beyond being shorter with slight dorsal spines. The opposing spine is very small. 

 The cirri are distally strongly compressed laterally. 



The radials are not visible. The IBr! are very short, markedly narrower than 

 the maximum width of the pentagonal axillary, and laterally free. The IBr 2 (axil- 

 laries) are short pentagonal with a somewhat depressed surface, laterally concave, 

 and proxirnally conspicuously broadened, rising to a synarthrial tubercle on the 

 articulation with the IBri. 



The arms are 10(?) in number. The first brachials are short discoidal, in con- 

 tact interiorly. The second are longer, laterally free, and distally broadened. The 



