284 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



adambulacrals. Granulation similar to that of superomarginals, 

 and a few similar pedicellariae are present. 



Actinal intermediate plates perfectly flat, in about 5 chevrons, and 

 irregular as to size and shape, but usually with 5 sides. Granules 

 similar in size to those of inferomarginal plates, but more spher- 

 ical or acorn-shaped. Sometimes 1 or 2 two- jawed entrenched pedi- 

 cellariae are present in an interradial triangle. 



First adambulacral with 7 or 8 slender compressed, blunt spines 

 in a nearly straight series. The first appearance of the apophysis 

 is in the second or third plate, but it does not become very prominent 

 until the eighth to twelfth. The spines gradually increase in num- 

 ber to 12, 13, or 14. The central 3 to 5 spines on the distal plates are 

 shorter and slenderer than the laterals, and on the proximal plates 

 they are slenderer and subequal. In short, they have the usual rela- 

 tions, and the distal plates are longer than wide. Subambulacral 

 granules rather variable. In the type there are 15 to 20, in about 

 3 series, several of the inner series being enlarged on the first 10 

 plates into short, granuliform, sharp tubercles. Near the adoral 

 border of a comparatively few of the proximal plates of type is a 

 2- or 8-jawed pedicellaria in the innermost suboral series. The jaws 

 are slender and curved inward. In specimens from stations 5423 

 and 5424, which in several details depart slightly from the type, 

 the pedicellariae are more numerous. In the specimen from station 

 5424 the pedicellariae usually have 3 jaws, and with a few exceptions 

 occur on all the first 25 to 30 plates. 



Mouth plates with a long and rather narrow mouth angle; mar- 

 ginal spines 12 to 15, usually 14 in type, similar to the furrow 

 spines but stouter and more compressed, gradually increasing in 

 size toward the inner angle of plate, most of the spines being thin, 

 petaloid, and round-tipped. Suboral granules 12 to 18; a series of 

 5 or 6 parallel to furrow series are enlarged into flattened tubercular 

 spines. 



Madreporic body larger than the primary basal plates, and situ- 

 ated about a third the distance from center to ambitus. It is sur- 

 rounded by 4 plates, with 2 others encroaching somewhat upon them. 



Gonads in a single tuft on either side of the membranous inter- 

 brachial septum. 



Type— Cdit. No. 30549, U.S.N.M. 



Type-locality. — Station 5491, between Leyte and Mindanao, 736 

 fathoms, green mud, coral; bottom temperature, 52.3° F. ; 2 speci- 

 mens. 



Distribution. — Sulu Sea to the Surigao Sea, north of Mindanao, 

 340 to 736 fathoms. 



Specimens examined. — Five, 2 from the type-locality and 3 from 

 the following stations: 



