292 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



2 broadly spoon-shaped denticulate jaws, the width of the rounded 

 or ovoid expanded part sometimes nearly equaling the total height, 

 which equals width of 2 or 2.5 peripheral granules. The base of 

 the pedicellaria is narrower than the rounded or ovoid distal portion 

 and the jaw is constricted just above the base. 



The edges of the plate fit together tightly, there being no inter- 

 spaces, and no papulae can be seen. The 5 primary interradial plates 

 can be distinguished by their slightly greater size. 



The papular area is very extensive and can not be seen from the 

 outside. It includes the whole dorsal surface, with the exception of 

 a band averaging 5 mm. wide, adjacent to the marginal plates, and on 

 either side of the interbrachial septum, extending inward nearly to 

 center of disk. Viewed from the coelomic side the abactinal plates 

 are even more regular than from an external view. The large pri- 

 mary plates of the radial area are roundish, with 6 to 8 facets, be- 

 tween each of which is a papula. The secondary plates are more 

 irregular, with 5 or 6 slight indentations separating the margin into 

 as man}' short lobes ; or there may be nq lobing but only 5 to 7 un- 

 equal facets. The lateral radial plates outside the area of intermedi- 

 ates are more regularly hexagonal. 



Superomarginal plates, 15 or 16 to the ray, the proximal 5 or 6 

 very tumid and abactinal in position, the succeeding plates less tumid 

 and with their transverse axis becoming more and more oblique to 

 the abactinal plane. First plate slightly wider than long; succeeding 

 5 or 6 plates longer than wide; the remaining plates shortening and 

 increasing in width so that the penultimate is wider than the plates 

 of the midregion of ray, but not quite so wide as the first 2 plates. 

 Granulation close and fine, similar to that of abactinal plate. Most 

 of the plates have 1 or 2 pedicellariae similar to the abactinal. The 

 first 4 or 5 plates have an irregular bare space in the middle, and in 

 this there are irregular groups and lines of granules. Some of the 

 outer plates show a similar bare space, but much smaller. Terminal 

 plate rather obovoid, or ovoid, and narrowed at either end. 



Inferomarginals confined mostly to side wall of ray, closely granu- 

 late, and often with a pedicellaria. General surface slightly arched 

 but not markedly tumid; first plate as wide as long; the next 7 longer 

 than wide and the remainder wider than long. The fifth or sixth 

 to fourteenth plates do not correspond in the 2 series but even alter- 

 nate. The plates of the 2 series have nearly the same area ; sometimes 

 the superomarginals are a shade larger, sometimes the inferomar- 

 ginals exceed, especially distally. 



Actinal intermediate areas very large, closely granulate, the gran- 

 ules convex and coarser than those of inferomarginal plates. Nearly 

 all the plates have 1 or, near the furrow, 2 entrenched pedicellariae 

 with 2 spatulate jaws often not so wide as those of abactinal surface. 



