274 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



specimens of leptodomus are all smaller the difference may not be 

 reliable. The first adambulacrals do not touch behind the mouth 

 plates. 



Madreporic body variable but fairly to decidedly large, sur-* 

 rounded by 6, 7, or 8 plates and situated about one-third the dis- 

 tance from center to ambitus. 



I have examined this species for rudimentary superambulacral 

 plates, but can find none. Gonads in 1 tuft on either side of the 

 membranous interradial septum. 



Variations. — One of the specimens from the type-locality differs 

 from the others in having a larger madreporic body, more convex 

 rays dorsally, but as the details of structure fit this species well I 

 have considered it an extreme variant. 



Type.— C2it. No. 30545, U.S.N.M. 



Type-locality. — Station 5216, between Burias and Luzon, 215 fath- 

 oms, green mud, bottom temparture 63.1° F. ; 5 specimens. 



Disti^hution. — Known only from region between Burias and 

 Luzon, 



Specimens examined. — In addition to the type, 6 from station 

 5388, between Burias and Luzon, 226 fathoms, soft green mud, bot- 

 tom temperature 51.4° F. 



Remarks. — N. leptodomus strongly suggests N. mucronatus on 

 account of the form of the abactinal radial plates, but the rays are 

 much narrower. The characteristic mucronate granules are absent 

 from the abactinal plates, there are numerous abactinal pedicellariae, 

 and the characteristic subambulacral spines of mucronatus are ab- 

 sent. From N. helli, leptodomus differs in having longer, narrower 

 rays; numerous abactinal and adambulacral pedicellariae; narrower 

 superomarginal plates ; larger madreporite, surrounded by more than 

 5 plates (4 in l)elli) ; a maximum of 10 or 11 furrow spines. 



NYMPHASTER MOLUCCANUS Fisher. 



Plate 64, fig. 3 ; plate 65, fig. 2 ; plate 68, fig. 7 ; plate 92, figs. 3, ^Or-h. 



Nymphaster moluccanus Fishee, 1913a, p. 037. 

 Diagnosis. — Similar in general form to N. euryplax, but radial 

 paxillae smaller, hexagonal, and not conspicuously widened: peta- 

 loid papular areas narrower and oral spines 10 to 12; marginal plates 

 rather broad ; ray broad at base, the width at inner end of the fii-st 

 pair of superomarginals which meet medially equaling length of first 

 4^ superomarginals measured on ambitus ; adambulacral plates with 

 strong furrow angle; minimum number of furrow spines at base of 

 ray 8 or 7; maximum number 10 (rarely 11). R=86 mm., r==21.5 

 mm. ; breadth of ray at midinterbrachium, 26 mm. 



Description. — Abactinal area arcuately pentagonal, as in most 

 species; the petaloid papular areas narrower than in euryplax, com- 



