352 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



to the inferomarginal plates. In 1 case there is a small isolated 

 intermarginal papular area with 7 papulae. 



The inferomarginal plates are for the most part opposite the su- 

 peromarginal, but become more numerous at the end of the ray, there 

 being 20 or 21. They are wider than long and oval in form, the 

 narrower end toward the furrow. The plates increase rather rap- 

 idly in size up to the middle of the ray, then decrease very gradually 

 to near the end of ray, then rapidly. They are very slightly convex, 

 but plane in the midle and paved with close-set polygonal granules, 

 which increase in size toward the outer margin, without attaining the 

 size of the largest superomarginal granules, except on the first 3 or 4 

 plates. These plates are smaller than the others, and covered by 

 granules which look as if they had flowed onto the plates from the 

 actinal intermediate area. The outer end of some of the plates 

 bears a low flattened tubercle. 



The small intermarginal plates are found both at the base of the 

 ray and irregularly near the tip. The proximal ones, numbering 

 7 to 10 extend one-third to one-half the length of ray; the outer 

 3 or 4 of these are isolated. Then, near the end of the ray are 2 to 4 

 small isolated plates at the corners of the marginals. On one ray 

 the series extends from interradius to near the tip, skipping only 2 

 marginals twice. There are about 18 plates in this series, some very 

 small. The first 2 or 3 usually have a central flattened tubercle, in 

 addition to polygonal, more or less elevated granules; the others are 

 granular. 



Terminal plate small, convex, abactinal in position. It is granu- 

 lar and shows the scar of a small terminal tubercle. 



Actinal intermediate plates in series from adambulacrals to mar- 

 gin, the first complete series leaving the fourth adambulacral and 

 meeting first inferomarginal. It abuts against the corresponding 

 series of the adjacent ray at the middle of r. In the angular area 

 thus inclosed, are less regular, more convex plates, the central gran- 

 ules very prominent, and sometimes tubercular. The other plates 

 are slightly convex, and covered with slightly spaced polygonal 

 granules (with rounded corners) 1 or 2 series on the margin of the 

 plates being considerably smaller than the rest. The plates adja- 

 cent to adambulacrals extend nearly to tip of ray ; the series parallel 

 to this is very irregular, but reaches nearly as far, its plates being 

 separated on outer part of ray by the inner end of the inferomargi- 

 nals. Eather small, low, beveled pedicellariae are present on the 

 plates adjacent to adambulacrals. 



Adambulacral armature like that of Oreaster. Furrow spines 8, 

 the 2 central about as long as the slightly curved furrow margin, "the 

 others rapidly diminishing in size, the laterals being only one-fourth 

 or one-fifth the length of the mesial. Subambulacral spines 2 (less 



