126 FISHER 



hollowed on inner face and occasionally is larger, springing 

 from a very low paxilla and emerging between the others. 

 Rarely there are 3 jaws. Jaws of pedicellariae much thicker 

 and more robust than any paxilla spines. 



Inferomarginal plates relatively very narrow, transversely 

 arched, encroaching but slightly upon actinal surface, forming 

 rounded margin to ray; chord of width equal to 1.5 times that 

 of adambulacral and actinal intermediate plates combined. 

 Fasciolar grooves deep and wide, slightly wider (/. e., meas- 

 ured on long axis of ray) than corresponding dimension of 

 specialized elevated ridge of plate. Each plate with a trans- 

 verse series of 3 robust, tapering, sharp spines, of which the 

 outer is often slightly the longest, but frequently the middle one, 

 or the 2 are subequal ; inner (actinal) spine of series is some- 

 times much slenderer than other 2, and only one half or two 

 thirds length of longest spine ; latter attains a length of 5.5 mm. 

 or slightly over one half width of abactinal paxillar area, or 

 nearly twice width of plate (/. <?., chord of width). General 

 surface of plate covered with slender almost capillary spinelets 

 which become finer in fasciolar grooves ; and upper end of plate 

 sometimes bears a pedicellaria similar to those of abactinal 

 surface. 



Adambulacral plates with a slender sabre-shaped furrow 

 spine, and forming a linear series with it on actinal surface, 2 

 slender tapering pointed spines, the inner of which is the stouter 

 and slightly the longer. A couple of very slender spinelets 

 stand on adoral side of outermost spine, which decreases in size 

 toward extremity of ray more rapidly than the inner. 



On most of the actinal intermediate plates of proximal two 

 thirds of ray is a small 2-jawed pedicellaria accompanied by 2 or 3 

 capillary spinelets ; when former is absent its place is taken by 

 about 3 to 5 capillary spinelets ; jaws of pedicellaria blunt, ob- 

 long to obovate, 0.5 mm. high ; 3 or 4 pedicellariae in interradial 

 region, but very few spinelets. 



Mouth-plates more like those of Astroficctcn than most spe- 

 cies of Luidia. Exposed surface of combined plates, ovoid, 

 prominent; suture between plates fairly wide. Armature con- 

 sisting of a slightly tapering, bluntly pointed tooth and back of 



