392 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Madreporic body large, with irregular, branched, centrifugal striae. 

 It is situated on the adradial series of plates, nearer to margin than 

 to center of disk. 



Anal aperture surrounded by about 6 subtriangular granules, larger 

 than the other granules. 



Type.—Q2ii. No. 32639, U.S.N.I^T. 



Tyjye-locality. — Port Palapag, north coast of Samar; no record of 

 depth or bottom, but probably collected on reef ; 2 specimens. 



Distribution. — Samar and vicinity, to 67 fathoms. 



Specimens examined. — The types and a very small specimen, prob- 

 ably belonging to this species from station 5482, Surigao Strait, east 

 of Leyte, 67 fathoms, broken shells, sand, green mud. 



Remarks. — This species is distinguished from the great majority 

 of Ophidiasters by having the adambulacral armature in 3 series. 

 It seems to require comparison chiefly with O. pusillus Miiller and 

 Troschel, from which it differs in having the papular areas in 8, 

 not 6, longitudinal series, in having the sheaths of the pedicellariae 

 toothed to correspond with the serrate blades, not entire as described 

 by Perrier (1875, p. 131). The granules are more tuberculate on the 

 center of the plates, especially the marginals, and the inner sub- 

 ambulacral spine is opposite an interval between 2 furrow spines, 

 whereas in pusillus Perrier states that this spine is opposite the 

 smaller of the furrow spines. 0. pustulatus von Martens is described 

 as having the furrow spines in 3 series, which would seem to ally it 

 with the present form, but Doderlein (1896, p. 317) believes that this 

 species is identical with O. purpureus Perrier, which is figured by de 

 Loriol (1885, p. 14, figs. 3-3A). 0. purpureus has the adambulacral 

 armature in 2 series, and furthermore is characterized by having a 

 granule between the furrow spines (and facing the furrow), a fea- 

 ture which it shares with 0. cylindricus Miiller and Troschel and 

 O. squameus Fisher. If Doderlein is correct, O. pustulatus is not 

 closely related to O. trychnus. But aside from this, 0. pustulatus has 

 longer rays (R=9 r) a more uniform granulation (not at all tubercu- 

 late), and less numerous subambulacral spines. 



The few Indo-Pacific species of Ophidiaster having the adambu- 

 lacral armature in 3 longitudinal series along the ray may be briefly 

 contrasted as follows : 



o\ Some of the abactinal antl marginal plates with a central tnbercle, or sev- 

 eral cons])icuous tuberculate granules, especially on the distal part of 

 the ray. 



6\ Excavate pedicellariae present; subambulacral spines of a plate con- 

 tiguous. 

 c\ Papulae normally in 6 longitudinal series; plates with single central 

 tubercle; sheath of pedicellariae with margin of depression entire, 

 not toothed or crenulate; papular areas large (except in young speci- 

 mens) with 10-12 pores 0. tuherifer Sladen 



(Andaman Islands, Sulu Archipelago, Torres Straits). 



