STAEFISHES OF THE PHILIPPINE SEAS. 269 



are not very great. N. mucronatus differs in the form of its peculiar 

 granules as well as in having wider plates, no abactinal or marginal 

 pedicellariae, conspicuous subambulacral spines, smaller .mouth plates 

 inclosed by the first adambulacrals, and more flaring sides to the 

 rays. N. leptodomiis has conspicuously narrower rays, less massive 

 marginals, and a generally more delicate habit. N. moluccanus 

 differs in having more symmetrical hexagonal abactinal radial plates, 

 wdder superomarginals, no abactinal or marginal pedicellariae, 10 or 

 12 mouth spines, more numerous and compact subambulacral granules, 

 and more uniform actinal intermediate granules. 



Nymphaster gardineri (Bell)^ from Say a de Malha Bank, western 

 Indian Ocean, 125 fathoms, is perhaps related to this species. T 

 liave examined the type in the British IMuseum, but, of course, was 

 unable to compare it directly with dyscritus. It resembles dyscritus 

 in general form and, like it, has few mouth spines (only 5 or 6 in 

 the marginal series), but differs in having the superomarginals of 

 disk and ray up to the seventh or eighth beveled in such a way that 

 they slope off from the median line of the proximal part of ray, as 

 in hdbrotatus. The dorsal edge of disk and ray is rounded, but 

 beyond the eighth superomarginal the ray becomes squarish in section. 

 Furrow spines 8 (6 on proximal plates) the apophysis of the plate 

 not well marked until the ray proper commences. On the surface 

 of the adambulacrals are 4 spines slightly shorter than the furrow 

 spines, and external to these, about 2 rows of granules with 3 in 

 each row, or an ellipse of 6. The inferomarginals are wider than 

 long up to the seventh (or sixth), then a plate is square (seventh or 

 eighth), beyond which the actinal face of the plates is much longer 

 than wide. In 10 inferomarginals, beginning with the sixth, there 

 are 16 to 18 adambulacral plates. No well-marked subambulacral 

 spine on outer part of ray. The median row of paxillae " trans- 

 versely " hexagonal, the granules being smooth and even. The sixth 

 superomarginal meets its fellow across ray, while the fifth is the 

 widest. 



N. gardineH falls under a^ of the key, but does not have the broad- 

 ened radial plates of euryplax nor the mueronate granules of mucron- 

 atus. 



NYMPHASTER MUCRONATUS Fisher. 



Plate 63, figs. 1, 2 ; plate 68, fig. 5 ; plate 69, fig. 6 ; plate 92, figs. 1, la. 



Nymphaster mucronatus Fishek, 1913a, p. 636. 



Diagnosis. — 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 mueronate granules ; 



^ Iconaater gardineri Bell, Trans. Linn. Soc. Lond., 1909-10, vol. 13, Zool., p. 22. 



