112 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



a*. Marginal plates not massive, the superomarginals being small, squarish, 

 and tumid, with a spine near center, and sometimes on the outer part of 

 ray more than 1 ; the inferomarginals narrow but with a well-marked 

 actinal face ; rays depressed ; pasillae ratht^r spaced and delicate. 

 & \ Rays broader ; inferomarginals at base of ray about two-thirds to three- 

 fourths as long as wide ; no actinal series of spiuules ; more than 1 

 series of suboral spines, the mouth plates as a whole larger; marginal 

 and subambulacral fasciculate pedicellariae ; furrow spines 6 or 7. 



oediplax, p. 127. 



b ^ Rays slenderer ; inferomarginals narrower, the width not exceeding 



length, except on first 2 plates ; 2 or 3 actinal inferomarginal spinules 



proximally, in addition to lateral comb ; only 1 series of suboral spines ; 



no marginal or adambulacral pedicellariae ; furrow spines 5 or 6. 



habrogenys, p. 131. 



PERSEPHONASTER EURYACTIS Fisher. 



Plate 24. fig. 4; plate 25, fig. 4; plate 30, fig. 5; plate 35. figs. 1, lor-d ; plate 36, 



fig. 1. 



Perse phonastcr curyactis Fisher, 1913«, p. 613. 



Diagnosis. — R=92 mm., r=23 mm., R=4 r; breadth of ray at 

 base, 24 to 26 mm. Eays depressed, broadly lanceolate, abruptly 

 constricted near tip into a very attentuate, sharp extremity; inter- 

 brachium abruptly rounded-angular; superomarginal plates broader 

 than long, and after the first half dozen, confined to abactinal sur- 

 face; each tumid plate with a transverse, appressed comb of 3 to 7, 

 flat, sharp spines; inferomarginals much broader than long, the 

 outer tumid end bearing a comb of about 5 prominent, sharp spines ; 

 proximal plates with a second lateral comb of 3 to 5 spines covered 

 by the first; curved furrow comb of 6 or T rather long spines; sub- 

 ambulacrals proximally about 6 in a single irregular series; actinal 

 intermediate plates extending two-thirds length of ray. 



Description. — Paxillae medium-sized, low, arranged in slightly 

 oblique transverse series on rays, meeting a narrow radial area of 

 irregularly arranged paxillae and a circular area on center of disk. 

 Largest paxillae on disk are found interradially at about the middle 

 of r, while on the rays the largest are in the lateral series near the 

 radial line, although there is not much diflFerence in size. At base of 

 ray 6 or 7 transverse series correspond to 2 superomarginals. The 

 spinelets usually stand erect in a compact flat-topped roundish group 

 causing the paxillae to be spaced about one-half their diameter apart. 

 "Whenever the spinelets radiate the paxillae at once appear larger 

 and closer together, even touching. Fifteen to 20 peripheral and 

 10 to 15 central slender, terete, blunt spinelets, longer than the 

 stout pedicel compose the crown of the larger paxillae. Many of 

 the paxillae bear a central fasciculate or pectinate pedicellaria con- 

 sisting of 4 to 8 jaws, considerably stouter but not much longer 

 than the regular spinelets. There are several giant paxillae on the 



