158 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



of ray. The difference in size is not great until the outer third of 

 ray is reached. The spinelets are slender, tapering, and pointed, 

 and are slightly shorter to slightl}^ longer than height of pedicel, 

 the latter being the variable feature. Usually they are borne in a 

 brushlike tuft, but sometimes radiate apart. A large paxilla has 

 15 to 20 spinelets, of which 3 to .5 stand on the convex top of the 

 pedicel and the others, with a slight basal web, form a peripheral 

 series. The distinction between the two sets is not sharp. When 

 dried, the spinelets are glassy in appearance and minutely thorny; 

 and the paxillae resemble, on a small scale, those of Grossaster 

 papposus. 



Scattered over the paxillar area and occurring rather commonly 

 around the border, are lower paxillae bearing globose pedicellariae 

 composed of 3 to 5 scalelike granules, or \Q,Yy low, broad, convex 

 squamiform papillae. The pedicellaria resembles a large globular 

 granule split nicely into 3 to 5 sections. 



Abactinal plates of ray have a generally broadly elliptical out- 

 line, but are irregular and often indented or scalloped. They are 

 spaced, except at end of ray and center of disk. Papulae, 4 to 6 

 about each plate, absent from end of ray and center of disk. 



Marginal plates rather small, regular, opposite, and square, as 

 seen from side, and forming a perpendicular lateral face to ray. 

 They are separated by pronounced and abrupt, vertical fascicles, 

 lined with delicate spinelets. Superomarginals, 37 to the ray, en- 

 croach very slightly upon the paxillar area, and, as seen from above, 

 are of about the same width throughout the series, this equaling 

 about one-half the height of the plates proximally, while distally 

 the height gradually lessens and becomes equal to the width. The 

 plates form an evenly rounded edge to the dorsal surface, and 

 each bears on this rounded margin between the dorsal and lateral 

 faces an erect, stout, conical, sharp spine 3 mm. long proximally 

 (or equal to 2 plates in length). Sometimes the spine is shorter. 

 The spinelets covering the plate are very similar to the paxillar 

 spinelets, delicate, tapering, or slightly swollen and sharp: and 

 when dried they are thorny, as are all the spines and spinelets. 



Inferomarginal plates encroach conspicuously upon actinal sur- 

 face, the actinal facet of the plate being wider than the lateral in 

 the interbrachium and about equal on distal half of ray. The cover- 

 ing of the plates is similar to that of the superomarginals, and simi- 

 larly on the angle between the actinal and lateral facets of plate is a 

 conical sharp spine subequal to or proximally a trifle larger than the 

 corresponding superomarginal spine, the series being very regular, 

 and the length decreasing toward the extremity of ray. 



Terminal plate as seen from above broadly arrow-shaped with a 

 deep indentation equal to half its length on the proximal side and 



