636 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 43. 



larise; narrower inferomarginal plates in the interbrachia; slightly 

 coarser actinal intermediate granules. Rays at inner end of first 

 pair of superomarginals which meet medially as wide as length of 

 first 3^ superomarginals measured on ambitus; interbrachia arcuate; 

 dorsal surface of ray nearly plane, with abrupt angles on the margin 

 of disk and ray. R = probably nearly 4 r; r = 23 mm.; breadth of 

 ray at mid-interbrachium, 26 mm. 



Type.—C&t. No. 30543, U.S.N.M. 



Type-locality. — Station 5526, between Negros and Siquijor Islands, 

 Philippine Islands, 279 fathoms, green mud; bottom temperature, 

 52.3° F. 



This species resembles in general appearance N. moluccanus, and 

 N. ternalis of Koehler (but not Perrier) from the Indian region. Very 

 likely the latter is a race of dyscritus. Koehler's species has more 

 regularly hexagonal abactinal plates, 8 adambulacral furrow spines 

 (maximum?), more numerous adambulacral pediceUarise (a variable 

 character), 8 or 9 mouth spines, and the apophysis commences 

 between the third or fourth and fifteenth adambulacral plates, vary- 

 ing on different specimens. 



N. dyscritus has the apophysis appearing on the first plate, but not 

 becoming conspicuous for 5 or 6 more plates. The first plate has 

 5 or 6 furrow spines which increase to 10, the laterals being broader 

 than the 2 or 3 mesial spines, which are compressed to an even thick- 

 ness, but are slightly tapering and round-tipped when seen from the 

 side, as indeed are the laterals. Subambulacral granules 10 to 14, 

 in about 3 series, the inner slightly longer than the outer. The fiist 

 few plates have a pediceUaria with 2 or 3 coarse, tapering, slightly 

 curved, bluntly pointed, spiniform jaws. 



N. dyscritus differs from the true N. ternalis (Perrier) in having 

 less tumid marginal plates, smaller abactinal radial plates, a sharper, 

 more abrupt angle to margin of ray, longer superomarginals in pro- 

 portion to their width (on ray) and in having the marginal apophysis 

 on all the adambulacral plates. 



NYMPHASTER MUCRONATUS, new speci'is. 



Very similar to N. euryplax in general form and in having the radial 

 plates wider than long, but "differing in having much less compact 

 radial plates with fewer and mucronate granules; larger madreporic 

 body; narrower inf eromarginals ; coarser, and more tuberculate, 

 sometimes mucronate, unequal, 'actinal intermediate granules; 

 smaller mouth plates, with the first adambulacrals nearly or quite 

 meeting behind them; many of the subambulacral spines of con- 

 spicuous size, and graduated into the tubercular granules of the 

 actinal intermediate plates. Rays broad at base, the width at 

 inner end of the first 2 superomarginals which meet medially equal- 

 ing first 4 superomarginals measured on ambitus; interbrachia arcu- 



