ASTEKOIDEA OF NORTH PACIFIC AND ADJACENT WATERS FISHER. 117 



be mi; notably smaller. Many of small paxillse of midradial area also bear in center 



of tabuluin, svirroimded usually by a few small poriphoral spinelets, a small obovoid 

 two-jawed valvate pedicellaria, resemblinf^ a split <,Tanule. Viewed from above, 

 the pedicellaria is elliptical in shape when closed. Each jaw is hollowed on inner 

 face and occasionally is lar<:er, sprin^inp; from a very low paxilla and emcr<^ing 

 between the others. Rarely there are three jaws. Jaws of pcdicellarife much 

 thicker and more robust than any paxilla spines. 



Plates, or bases of paxillae, are cniciform along; either side of area, leavinc; large 

 quadrate spaces for the papulre. Superomarginal plates very much larger than 

 adjacent abactinal plates, and cruciform in shape also, but with verj"- much broader 

 lobes, the arms on the longitudinal axis being longer than those on the transverse. 

 Inferomarginal plates also four-lobed (as seen from the inside), there being con- 

 spicuous roundish spaces between the infero and superomarginal series, correspond- 

 ing to the papular spaces on dorsal surface. Plates decrease very rapitlly in size 

 toward radial line, are irregular, frequently have five lobes, and on median radial 

 area are roundish and crowded, without papula; between. Thus along the radial 

 area of ray there is a band of var^-ing width free from papula?. 



Inferomarginal plates relatively very narrow, transversely arched, encroaching 

 but slightly upon actinal surface, forming rounded margin to ray; chord of width 

 equal to one and one-half times that of adambulacral and actinal intermediate plates 

 combined. Fasciolar grooves deep and wide, slightly wider (i. e., measured on long 

 axis of ray) than corresponding dimension of specialized elevated ridge of plate. 

 Each plate with a transverse series of three robust, tapering, sharp spines, of which 

 the outer is often shghtly the longest, but frequently the middle (me or the two are 

 subequal; inner (actinal) spine of series is sometimes much slenderer than other 

 two, 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 the width of plate (that is, chord of width). General surface of plate covered 

 with slender, almost capillary spinelets, which become finer and more densely placed 

 in fasciolar grooves, and upper end of plate sometimes bears a pedicellaria similar 

 to those of abactinal surface. 



Adambulacral plates with a slender saber-shaped furrow spine and forming 

 a linear series with it on actinal surface, two slender, tapering, pointed spines, the 

 inner of which is the stouter and slightly the longer. Except in small specimens, 

 one to three very slender spinelets stan<l on adoral side of outermost spine, which 

 ilecrcascs 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 two-jawed pedicellaria accompanied bj- two or three capillary spinelets; when 

 former is absent its place is taken b}' about three to five capillary spinelets; jaws of 

 pedicellaria blunt, oblong to obovate, 0.5 mm. high; three or four pedicellaria! in 

 interradial region, but very few spinelets. 



Mouth plates more like those of Astropecten than most species of Luidia. 

 Exposed surface of combined plates, ovoid, prominent; suture between plates fairly 

 \vide. Armature consisting of a slightly tapering, bluntly pointed tooth, and back 

 of that on margin a large two-jawed pedicellaria nearly as long as tooth. Two 



