102 ZOROASTEKIDAE. 



DD.< Adambulacral plates with only one transverse series of actinal spines. 



E.' Abactinal surface with coarse spinulation and numerous big pedicellariae . . . .ophiwus. 

 EE.' Abactinal surface with fine spinulation and few inconspicuous pedicellariae. 



F.^ Carinal plates at base of arm quadrilateral much wider than long; superomarginals 



similar but smaller ackleyi adult. 



FF.2 Carinal plates about as long as wide with lateral margins more or less deeply notched; 

 superomarginals irregularly diamond-shaped with rounded angles, not much wider 

 than long. 



G.' Adambulacral furrows with few pedicellariae carinatus. 



GG.' Adambulacral furrows with many pedicellariae carinatus philippinensis. 



Zoroaster peraxmatus,' sp. nov. 

 Plate 4, fig. 2. 



R = 98 or 125 mm.; r = 13 or 18 mm.; R = 7-7.5 r. Disk moderately 

 large, not elevated above nor distinctly set off from rays. Primary plates 

 distinguishable but not conspicuous and not at all swollen Rays rather stout, 

 the height at base equalling or exceeding the width, which is about .15-.17 of the 

 length; rays tapering to a blunt tip, more slender in the larger specimen than in 

 the smaller. Carinals moderate, wider than long, lateral margins narrowed 

 by large papular areas. Adradial plates moderately well -developed, at least on 

 basal part of arm, much longer than wide and nearly quadrilateral. Supero- 

 marginals similar to carinals but only about half as large. Inferomarginals 

 similar but somewhat smaller and relatively longer. Actinolaterals in fom- 

 series (on basal part of arm), nearly square and closely joined, the papular pores 

 being very small. There is no indication of imbrication among either the 

 marginal or actinolateral plates. Madreporite 2-3 mm. across, rather prominent, 

 close to disk-margin, surrounded by five or six spinelets. 



The gi-eat majority of the skeletal plates are more or less elevated at or 

 near the middle into a conspicuous spine-bearing tubercle ; the spine on the disk- 

 plates, carinals, marginals, and adradials being stout and erect, .75-2 mm. 

 high and .30-.90 mm. tliick at base; on the actinolaterals the spine is often 

 wanting but when present reaches a length of 5 mm. and a thickness of 1 mm. 

 at base; in the smaller specimen, the spines are all erect, standing out at right 

 angles to the plate-sm"face, but in the larger specimen, the actinolateral spines 

 are all more or less appressed to the sides of the ray. On the disk-plates, carinals, 

 adradials, and marginals, there are no secondary or 7niliary spines whatever, 

 but there are mmaerous big pedicellariae, 1-2 mm. long. Actinolateral plates 

 weU-covered with rather stout spinelets, about ten to a plate; in alcohol, these 

 spinelets are conspicuously sacculate but when dry the saccvile disappears and 



'^perannatus = thoroughly armed; in reference to the extreme development of primary spines. 



