2J4 BULLETIN 7G, UNITED STATES NATIONAL MUSEUM. 



lobes forming regular transverse and longitudinal series (except on area of irregular 

 puxilhe wliic'h have a three to five lobed base). On the distal part of ray the plates 

 all have w-ider and shorter lobes, even those of the lateral series, which acquire an 

 arcuate quadrate contour and may rarely be arcuately pentagonal. Papula four 

 about each plate, large on the lateral portions of ray, very small in center, and 

 irrcnilar there. Papulic are compound. Numbers of them are invaginated into 

 body cavity and gorged \\-ith granular substance as if actively excretory. This 

 is sifniilcant when considered in connection with the absence of an intestinal ccecum 

 and anal pore. 



Inferomarginal plates relatively narrower than in foliolata. Fasciolar channels 

 deep, about as wide as the tliickness of the intervening elevated ridges. Outer or 

 abactinal end of each plate \\'ith a two-jawed (rarely three-jawed) pedicellaria 

 similar to that of adjacent supcromarginal paxilla, and with one or two, usually two, 

 tapering sharp spines, of wliich sometimes the imier, sometimes the outer, is the 

 longer; the longer (about 4 mm.) equal to about \\ddth of its plate; more rarely 

 three shorter subequal spines in transverse series on outer end of plate. The 

 spines form a prominent marginal fringe to raj-. On actinal surface of plate three 

 to six much shorter spinules form a transverse series in line with lateral spines, or a 

 zigzag, or even double series, wliilc margin of plate bears numei'ous unequal spinelets, 

 becoming more capillary in fasciolar grooves. Only the outer part of the furrows 

 is hned with tlic minute filtering spinelets. Considerable variation exists in the 

 details of arrangement and number of auxiliary spinules. They are usually blunt 

 and more or less flattened. From the actinal surface the marginal spines are 

 decidedly conspicuous. 



Adambulacral armature consisting of a curved saber-shaped furrow spine, 

 and on actinal surface three tapering, bluntly pointed, sometimes quite slender, 

 spines, of which one, the longest, often strongly compressed and also saber-shaped, 

 stands behind furrow spine, and the other two form a sUghtly obhque longitudinal 

 series just behind first actinal spine; or two spines, the adoral the shorter, stand in 

 a longitudinal series just behind furrow spine, and the third just outside of the 

 aboral (longer) spine of the series; one to three small slender spinelets occur on 

 outer part of plate, frequently three at base of ray forming a longitudinal series, 

 or one on adoral edge of plate, back of outer adoral spine. At base of ray the 

 three iimer actinal spines form a triangular series on margin of plate (the furrow 

 spine being liigher in furrow), and behind them are usually two or three other 

 spines. Two spines arc sometimes associated to form a sort of incipient pedicellaria. 



Actinal intermediate plates of interraclial region and proximal half of ray paxilli- 

 form, surmounted by a prominent three-jawed pedicellaria which is surrounded 

 at base by numerous slender spinelets in a calyx-like whorl. Each pedicellaria is 

 conical and one and one-half to two times as high as its width at base. The inter- 

 mediate plates extend nearly to tip of ray, but on its outer third are very small 

 and usually without spinelets. They can be seen readily if ray is soaked in caustic 

 potash solution. Besides the jjrimary row of intermediate plates, in each inter- 

 radius there are one to five additional plates. 



