200 Bulletin American Museum of Natural History. [Vol. XXXII, 



ous and median radial series on arms not much larger than superomarginals; all of 

 the larger plates carry spines and scattered well-spaced spinelets; on each plate 

 there is a central spine, 1-2 mm. long, stout and more or less blunt, and there may be 

 also two or three smaller spines, but the latter are not very constant in number or 

 position; pedicellaria? occur on most of the plates, but the largest of them are much 

 smaller than the central spine. 



Between the median radial series of plates on each ray and the superomarginals 

 there is only an incomplete series of small plates, and these are found only at the 

 very base of the ray; the superomarginals are nearly as large as the median plates 

 and the inferomarginals are little smaller; between the latter and the adambulacrah 

 are three series of actinolateral plates, the uppermost of which are nearly as large as 

 the inferomarginals and the lowermost are much smaller, nearly quadrilateral and 

 about three times as long as high. Each marginal and actinolateral plate carries a 

 central spine, and a few small spines or spinelets, well spaced and mingled with 

 pedicellaria?; the spines on the superomarginals are like those on the median series; 

 those on the inferomarginals are imperceptibly longer; those on the uppermost 

 actinolaterals are longer and slightly flattened near the tip; those on the second 

 series of actinolaterals are the longest (3-4 mm.) and are very wide and flat; those 

 on the lowest actinolaterals are a little shorter, somewhat more slender and are less 

 flattened. All three series of actinolateral plates are continued nearly if not quite 

 to the tip of the ray. 



Between the lower series of actinolateral plates, there are no papular areas, 

 but between the upper and second series, the areas are as large as abactinally. Be- 

 tween the median and the superomarginal plates the papular areas are arranged in a 

 double, alternating series. Elsewhere these areas are in single longitudinal series. 

 There is only one papula to each area, and while it is large, it does not occupy all of 

 the area, by any means. 



The adambulacral plates are arranged as usual in the genus, plates projecting into 

 the furrow alternating with those which do not. The plates are separated from 

 each other by distinct, membranous spaces; each plate is about three times as wide 

 as long. On the projecting plates is a single series of four or five slender spines, the 

 first of which is well up in the furrow; the second and third are about on the 

 rounded angle of the plate, and the fourth (and fifth, when present) are on the actinal 

 surface; the fourth spine (or fifth) is the smallest and more or less distinctly sacculate 

 at tip; the second and third spines are of about equal size (2 mm. ±) or the 

 third is largest. On the non-projecting plates are two or three spines, of which the 

 first is largest and about equals the third spine of the alternating plates; the other 

 spine (or spines) is slightly sacculate at tip. Pedicellarise are not specially abun- 

 dant; each furrow spine may carry one to three but many have none; in the inter- 

 radial angles are a very few pedicellarise larger than elsewhere, and these may be 2 

 mm. long. Oral plates very short (as usual in Zoroaster), each with two marginal 

 and two suboral spines, 1-2 mm. long; the distal marginal spine carries a cluster cf 

 three or four small pedicellarise. 



Tube-feet in four distinct series. Madreporite smaller than a primary disk-r 

 plate, situated about half-way between center of disk and margin. Terminal plate 

 of ray moderately large, with two spinelets at the tip and numerous much smaller 

 ones crowded over its surface. Color completely lost in the preserved specimens 

 which are dingy brownish-yellow. 



Type. Cat. No. ■ , U. S. N. M. from Station 5675 (not yet catalogued). 



