390 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Station 5641, off Kalmo Point, Buton Strait, Celebes, 39 fathoms, 

 sand, shells; 1 specimen. 



Remarks. — Koehler (1910«, p. 149, pi. 18, figs. 5 and 6) has de- 

 scribed a very closely related form, 0. Mrsutus from the Andaman 

 Islands, 11 to 25 fathoms, which may prove to be but a race of fuscus. 

 It lacks pedicellariae and has an inconspicuous actinal intermediate 

 series of papulae at base of ray, as well as a few other minor differ- 

 ences, including color. 



I have examined a specimen of Linckia Tnegaloplax from the Alert 

 collection (Museum of Comparative Zoology) and I think it is very 

 probably the same as Ophidiaster fuscus. 



OPHIDIASTER TRYCHNUS Fisher. 



Plate 84, fig. 5 ; plate 95, figs. 6, Qa-d ; plate 103, figs. 2, 3 ; plate 107, fig. 6. 

 Ophidiaster trychnus Fisheb, 1913o, p. 215. 



Diagnosis. — Differing from 0. pusillus Miiller and Troschel in 

 having the papulae in 8 longitudinal series, and the central granules 

 of the abactinal, marginal, and actinal plates enlarged, and subtu- 

 berculate on outer part of ray, and in having the pedicellaria sheaths 

 toothed, not entire; differing from O. tuberifer in having 8 longi- 

 tudinal series of papular pores, much larger and broader pedicel- 

 lariae, with the sheaths toothed, not entire, and in having a number 

 of enlarged granules on the plates, not a single conical tubercle of 

 predominant size. R=19 mm., r=4 mm., R=about 5 r. ; breadth of 

 ray at base, 5 mm. Eays cylindrical, only very slightly tapering, with 

 a blunt extremity capped by a dorsal, convex, roundish terminal 

 plate. 



Description. — Seven series of abactinal and marginal subcordate 

 plates, the adoral narrower end overlying the broader aboral end ; 2 

 series, on either side, of smaller actinal intermediate plates, the inner 

 extending to within 4 inferomarginal plates of end of ray, the second 

 extending nearly half the length of ray. Abactinal and marginal 

 plates slightly tumid, each longitudinal series forming a low convex 

 ridge, separated by relatively shallow, but very evident, furrows, con- 

 taining the series of papular areas (8 in all). Granules slightly 

 spaced to contiguous, but not crowded; very unequal as to size and 

 form. Those covering papular areas are small and unequal, but 

 usually a little smaller than the pores themselves; next larger are 

 the granules between consecutive pore areas and along the transverse 

 margins of the plate, whence they increase very rapidly in size toward 

 the center of plate, the greater part of whose area is occupied by 

 blunt, broadly subconical, unequal, sometimes tuberculate granules, of 

 which 3 to 10 are of preeminent size, and either touch or are very 

 slightly spaced, the groups being usually wider than long — that is, 



