STAEFISHES OF THE PHILIPPINE SEAS. 471 



d^ Rays long, slendei-, disk small; abactinal, marginal, and actinolateral 

 plates arranged in regular longitudinal lines along ray, a series of 

 adradial plates being always present; all but the median radial, or 

 carina!, which are longer than the I'est, form also transverse series 

 with one another ; plates covered with small papilliform skin- 

 covered spinelets, and most of them bear an enlarged spine; papular 

 areas small; forficiform pedicellariae present; actinolateral plates 

 In 3 to 5 series, the upper subequal to the inferomarginal plates; 

 superomarginal plates not conspicuously larger than inferomarginal 



plates Zoroaster Thomson. 



dj' Abactinal plates arranged in regular longitudinal series (the carinal 



plates the largest), bearing large skin-covered scales, which mask 



all plates except some of the primary apical plates of disk, and 



the carinal series of ray; no pedicellariae; actinolateral plates in 2 



or 3 series, much smaller than the inferomarginals ; superomarginal 



plates much larger than infei"omarginal plates. Pholidaster Sladen. 



6* Superambulacral plates present; a conspicuous buttress, the specialized 



first superambulacral plate connects the upper end of the first 2 ambula- 



cral plates with body wall at interradius. 



c^ Well developed adradial plates ; with 2 series of well developed papular 



areas between the carinal and superomarginal plates, the latter not 



conspicuously enlarged nor overlapping the carinals. Myxodcrma 



Fisher. 



c* No adradial plates ; 1 series of very small adradial papular pores ; 



superomarginals alternating larger and smaller, overlapping strongly 



and dominating the carinals which are sunken below the level of the 



superomarginals BytMoloplms, Fisher. 



' Abactinal plates of disk, the carinals, adradials (when present), marginals, 

 and sometimes one series of actinolateral plates devoid of spines or any 

 conspicuous armature but mostly smooth and covered with a tough mem- 

 brane of variable thickness, often partly obscuring the plates; 2 to 4 

 lower series of actinolateral plates covered with squamiform fleshy spine- 

 lets and with sometimes a conspicuous appressed spine; superambulacral 

 plates present, the first conspicuously enlarged into a buttress connecting 

 upper end of first 2 ambulacral ossicles with the body wall. 

 6^ With a series of adradial plates more or less well developed ; 4 or 5 series 



of actinolateral plates Cnemidastcr Sladen. 



6* Adradial plates absent, the inner lobe of the superomarginal plates over- 

 lapping the carinal plates; 3 series of actinolateral plates with the 

 beginning of a fourth in large examples Mammaster, Perrier. 



Genus ZOROASTER Wyville-Thomson. 



Zoroaster Wyville Thomson, Depths of the Sea, 1873, p. 154. Type, 

 Z. fulgens Thomson. 



KEY TO SPECIES HEREIN DESCRIBED. 



. Carinal, marginal, and lateral plates all with central spine; carinal spine, 

 stout and conical ; marginal and lateral spines acicular, prominent ; pedi- 

 cellariae long and slender, usually 4 times as long as width at base; 

 miliary spinelets long, very slender, spaced opliiactis, p. 473. 



