246 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



lation similar to that of superomarginalfe. A small entrenched 

 2- jawed pedicellaria on some of the first plates of type, but not in 

 other specimens. 



Actinal intermediate plates four-sided, in 2 or 3 regular chev- 

 rons, according to the size of specimen, slightly raised, with con- 

 spicuous sutures, and covered with spaced tubercular subprismatic 

 granules, often longer than wide and intermediate between short 

 spines and granules. The largest have 12 or 14 of these. 



Adambulacral plates small, squarish, with a nearly straight furrow 

 margin proximally and a slightly curved one distally, but no angular 

 projection or apophysis as in Nymphaster. Furrow spines 4 or 3 in 

 small specimens, but in the type proximally 4, then 5 over the greater 

 part of the ray, then 4 at tip, short, compressed, blunt. Spaced from 

 these is a parallel series of 3 (proximally) or 4 stouter, slightly 

 shorter, blunt, subprismatic to subterete subambulacral spines, the 

 adoral the shortest when there are 4. Spaced from these is a par- 

 allel series of 3 or 4 subprismatic granules, the tip either blunt or 

 beveled like that of a chisel. 



Mouth plates with 6 compressed round-tipped marginal spines 

 in a straight series and about 8 suboral spines and granules, 3 or 4 

 forming a series parallel to furrow; 2 more, slightly smaller, aro 

 parallel to these, while the outer end of the plate is occupied by 



2 or 3 granules. 



Madreporic body medium sized, sun'ounded by 5 plates (4 in 

 young) situated about halfway between center and edge of mar- 

 ginals. 



Anatomical notes. — Although the specimens are small, the gonads 

 are relatively very large and fill up most of the coelom of the base 

 of ray. They consist of thick imbranched or bifid sacs in clusters of 

 1 to 5, these extending in a series close to the margin as far as the 

 third superomarginal or until these join medially. There seem to be 

 at least 5 of these clusters in each series. The stomach is rather 

 small. There are no superambulacral ossicles or rudiments. 



Variations. — Aside from the variations referred to in the descrip- 

 tion, the proportion of R to r differs individually and according to 

 size. In the smallest example R=13 mm.; r=: 4 mm.; R=3.2 r; an- 

 other specimen measures R=17.5 mm., r=6.5 mm., R=2,7 r. A 

 smaller specimen measures 16.5 mm.; r=5 mm., R=3.3 r. 



Type.— Cut. No. 30539, U.S.N.M. 



Type-locality. — Station 5152, Tawi Tawi Group, Sulu Archipelago 

 (lat. 5° 22' 55'' N.; long. 120° 15' 45" E.), 34 fathoms, white sand; 



3 specimens. 



Distribution. — From east of northern Palawan to the Sulu Archi- 

 pelago, 34 to 51 fathoms, on sandy bottom. 



