no. 1827. NEW GENERA OF STARFISHES— FISHER. 425 



Actinal interradial areas large, irregularly disposed, nearly flat, 

 granulated, and with pedicellarios. They extend about to the middle 

 ofR. 



Adambulacral plates with angular furrow margin but the angle 

 nearer the adoral side, so that the facets are veiy unequal. Spinelets 

 10 to 12, rather short, round-tipped or truncate, in a crowded series, 

 the longest on the angle and compressed in a plane transverse to 

 furrow, the others gradually shortening and with flat side to furrow. 

 Actinal surface of plates with crowded low conical granules and occa- 

 sionally a pedicellaria. 



Mouth plates nearly flat, coarsely granulate, with 16 to 18 marginal 

 robust spinelets, increasing in size toward inner angle. The furrow 

 surface of each plate has a shallow vertical depression for first tube 

 foot. 



Madreporic body one-third minor radius from center. Tube feet 

 with strong disks; ampullar double. 



Type-locality. — Station 5655, Gulf of Boni, Celebes; 608 fathoms; 

 gray mud, fine sand. 



Type.— Cat. No. 28659, TJ.S.N.M. 



Remarks. — The new genus is quite unlike any other and probably 

 belongs in the Leptogonasteringe, although further study may warrant 

 placing it in the Goniasterinae. It is somewhat intermediate. The 

 large overhanging superomarginals and flat granulate membrane- 

 invested plates, which are however distinct, are the most trenchant 

 features of the genus. 



Family PTERASTERID^E. 



HYMENASTERIDES, new genus. 



In general structure similar to Hymenaster but with two kinds of 

 adambulacral plates alternating; (1) prominent plates bearing a 

 transverse series of 3 rather long slender spines, and (2) nonprominent 

 plates with only 1 spine. Tube feet in 4 series, the feet of the 

 outermost series corresponding to the nonprominent plates. Com- 

 bined mouth plates produced actinally into a cone, the apex of which 

 is about the middle of median suture. Two suboral spines. 



Type. — Hymenasterides zenognathus, new species. 



HYMENASTERIDES ZENOGNATHUS, new species. 



Diagnosis. — Paxillar area raised above the actinolateral membrane 

 which forms an even narrow border; paxillse in 9 longitudinal series, 

 5, or laterally, as many as 7 spines to a paxilla, one being longer than 

 the rest; no visible muscle-fibres; scattered spiracula. Prominent 

 adambulacrals with 3 slender membrane invested sacculate spines; 

 nonprominent with one, each of which is opposite a tube foot of outer 

 series. Mouth plates conical actinally with 2 suborals, and 3 or 4 



