206 BULLETIN 100, UNITED STATES NATIONAL MUSEDM. 



Description. — Abactinal area plane, slightly lower than the mar- 

 ginal plates, which form a broad border to the area. Abactinal 

 plates low, slightly convex, not at all paxilliform, and bearing small, 

 prickly, sharp granuliform spinelets. The largest plates, on the 

 papularia, have upward of 10 to 12 peripheral and 2 to 4 central 

 granules, while on the proximal part of the ray 1 or central and 

 5 to 8 peripheral granules are found. The number of granules de- 

 creases toward the end of the ray. On the outer third the number 

 is reduced to 2 or 3, and on the distal fourth, to 1. The group-: 

 of granular spinelets are rather uniforml}^ spaced on the disk and 

 proximal half of ray one-third to one-half the width of the group. 

 No enlarged central spines and no pedicellariae. 



Papularia large, as long as the first 4 superomarginals and as broad 

 as the length of the first 3, strongly two-lobed. In fact, each papu- 

 larium is double and joined only at the adcentral end. There are 

 about 80 pores to each. 



Anal opening prominent, guarded by 6 plates with longer spinelets 

 than elsewhere on the area. 



Superomarginals 22 or 23, encroaching broadly upon the abactinal 

 area, slightly tumid, especially toward ambitus, and separated by 

 prominent, oblique, smooth grooves. The armature is peculiar. 

 About the first 10 plates bear on the rounded margin between the 

 dorsal and lateral facets of the plate a short, stout, pointed tubercle, 

 proximally acorn-shaped, which is shorter there than the length of 

 plate. This spine increases slightly in length and decreases in thick- 

 ness distad. Beyond the tenth, the plates are more tumid, and each 

 bears a transverse series of 3 subequal, tapering, rough spines which 

 occupy the whole width of the plate. Proximally they are a little 

 longer than their plate, and near the end of the ray are equal to 

 about 3 plates in length. Parallel to the major spines is an adoral 

 series of 3 accessory spinules, while aborally there is an enlarged 

 spinule which often is nearly as large as the major spines, and is 

 associated often with 1 or 2 nnich smaller spinules. This abrupt 

 transition from 1 to 3 superomarginal spines gives a very character- 

 istic appearance to the armature of the superomarginals, as the 

 distal spines are bent over and usually cover the abactinal area. 

 General surface of plates covered with small widely spaced spinelets 

 similar to those of the abactinal area, which become larger on the 

 low lateral face of plate. The terminal plate is prominent, wider 

 than long, and covered with spines. 



Inferomarginal plates slightly tumid, bearing a single lateral, 

 tapering, sharp spine, a little longer than its plate proximally, and 

 regularly and gradually decreasing in size toward end of ray. The 

 first 4 or 5 plates have 1 or 2 small accessory spinules forming a 



