ASTEEOIDEA OF NORTH PACIFIC AND ADJACENT WATERS FIbHER. 87 



below), the shaft with spinelets being 3.5 to 6 mm. liigh in larger specimens. This 

 shaft or pedicel is surmounted by a globular or elongate crown of very numerous, 

 slender spinclets sheathed in delicate membrane, the whole forming a dense glomeru- 

 lar tuft, the central or uppermost spinelets bluntly tipped, but those on the side 

 mucronate, less crowded, and usually extending in a bristling arrangement down the 

 sides of pedicel, for nearly to over one-half its length. In the latter case the paxilla 

 resembles a minature bottle-brush. In a dried specimen the centrally situated 

 spinelets are much sharper, due to a shrinkage in the membranous envelope. 



The abactinal plates or bases of paxillae are strongly lobed on center of disk and 

 along median radial area, the lobes becoming less prominent toward margin of abac- 

 tinal area. Some plates have six, some four, some five lobes, and they are very irreg- 

 ular. On the regular lateral rows of plates there is more uniformity, but here some 

 plates have five divisions while the majority have four. Near center of disk numer- 

 ous plates are rounded or irregular without evident divisions. In another specimen 

 examined the plates are much more regular especially along the lateral rows. Here 

 they touch or sliglitl}' overlap by lateral lobes, which does not take place in the first 

 example. Some plates near the margin of interradial area are nearly square. 

 PapulsB are distributed all over abactinal paxillar area, from tip of ray to center of 

 disk. There are usually six about each plate, but where the plates are not aiTanged 

 in regular rows there are often more, especially in the case of the median radial series. 

 Wlien viewed from the outer surface, the papular areas are seen to be larger here, and 

 to contain two or three papula^, instead of one, as is usual. Thus a carinal or radial 

 plate may be surrounded by twelve to eighteen or twenty papulae in groups of two or 

 three, these papulie being of course common also to several adjacent plates. 



Marginal plates massive and regular, the inferomarginals defining contour of 

 ray, and extending laterally beyond superomarginals for a variable distance which is 

 sometimes (as in type) equal to width of latter. Superomarginals, over thirty 

 (thirty-two to thirty-four) in large specimens, are slightly wider than long, and 

 shorter in proportion to width in interbrachial angle than farther along ray. They 

 are completely confined to abactinal surface, and form an archeil bevel to margin of 

 paxillar area. The exposed surface which is slightly tumid, is covered with small 

 but robust polygonal flat-topped spinelets in middle, these rapidly becoming slen- 

 derer toward edge of elevated ridge, where the}' are either blunt or sharp; and are 

 longer on outer than on inner edge of plate. Nearly all the plates bear a tubercular, 

 short, polygonal stumpy spine either near middle or in outer aboral quarter of plate. 

 In some specimens there is a group of two or three such tubercles, which do not ex- 

 tend conspicuously above the general covering of plate, except in rare cases, but 

 are larger on outer part of ray than on proxinal portion. 



Inferomarginals correspond exactly to superomarginals, are much wider than 

 long, and form a conspicuous border to actinal surface. On outer end of each plate 

 (or rather the specialized ridges) is a transverse series of four to six stout tubercular 

 spines the upper or next to upper longest, forming an armature on margin of ray. In 

 some specimens (usually small to medium-sized) these spines are tapering and rather 

 sharp, but usually on large examples are truncate and thicker at tip than at base; 

 and the tip is also usually truncated obliquely, due to the spines being bent toward 

 tip of ray. Near base of ray the thick spines may have the tip curiously hollowed 



