610 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.43. 



about 90°, rounded; superomarginals with a single row of prominent 

 appressed spines, extending nearly to tip of ray; inferomarginals 

 with 2 series, one near the upper end of the plates and the other near 

 the lower; adambulacral plates with 7 or 8 furrow spines proximally, 

 and about 10 subambulacral spines in 2 series; mouth plates with a 

 horizontal fan of 4 prominent teeth. Differs from Ps. agassizi 

 (Koehler) in having only 1 superomarginal series of spines, no well- 

 defined central naked area on inferomarginals, and in having the 

 superomarginals less conspicuous, dorsally, and the inferomarginals 

 practically confined to the sloping side wall of ray; furrow spines 

 slightly more numerous. 



Type.— Csit. No. 30517, U.S.N.M. 



Type-locality . — Station 5468, Lagonoy Gulf, southeastern Luzon, 

 569 fathoms, green mud. 



Tliis, as well as the following form, come within the restricted 

 group Phidiaster of Koehler. 



The species is named in honor of Dr. Seitaro Goto, of the Imperial 

 University, Tokyo. 



PSILASTER ROBUSTUS, new species. 



11 = 30 mm., r = 9.5 mm., 11 = 3.15 r; breadth of ray at base, 12 

 mm.; height of combined marginal plates at middle of interbrachium, 

 6 mm.; disk large, rajs stout and short, evenly tapered; supero- 

 marginal plates very rfiassive, encroaching conspicuously upon 

 paxillar area, than which they are wider at middle of ray; paxillae 

 small, spaced; one series of superomarginal spines; one series of 

 lateral inferomarginal spines and an incomplete second (ventral) 

 series at base of ray; marginal plates covered with squamules and 

 without naked areas; furrow spines 6 or 7. Differing from Ps. gotoi 

 in having much more massive superomarginals, which encroach more 

 upon paxillar area, smaller paxillae, thicker terminal plate, only 1 

 complete series of inferomarginal spines, shorter and more globose 

 suboral spines, sHghtly shorter adambulacral spines, and a thicker, 

 more robust, form. 



Type.— Cat. No. 30518, U.S.N.M. 



Type-locality.— Stsition 5632, south of Batjan Island, Molucca 

 Islands (lat. 1° S.; long. 127° 50' E.), 845 fathoms. 



The paxillar area is sunken below the level of the broad tumid 

 superomarginal border, the paxillas being small, with about 12 

 coordinated, close-set spinelets on the largest plates of interradial 

 portions of disk. The superomarginal spine is near the inner edge of 

 the first 2 plates, but on the third is about twice as far from the inner 

 edge, and on the fourth stands on the rounded border between the 

 dorsal and lateral faces of the plate. Beginning with the second or 

 third inferomarginal plates is a row of sharp, prominent, flattened 

 spines, slightly larger than the superomarginal, extending nearly to 



