126 BULLETIN 100, UNITED STATES NATIONAL MUSEUM, 



aboral margin of the plate, not in the center ; inf eromarginals appre- 

 <;iably broader, with less crowded squamules; furrow spines 7 or 8; 

 marginal fan of mouth spines prominent, 5 to 7, nearly as long as 

 first adambulacral furrow spines. R=61 mm., r=14 mm., 11=4.3 r; 

 breadth of ray at base, about 16 mm. 



Description. — The difference in the appearance of the abactinal 

 surface of suluensis and multicinctus is chiefly due to the more evi- 

 dent tumidity of the latter's superomarginals, and the position of 

 the summit of this on the median transverse line of the plate — not 

 near the distal margin. The superomarginals of suluensis are not 

 ■evenly rounded from the inner to the lower or outer margin but have 

 a fairly plane and horizontal dorsal facet at nearly right angles to 

 the lateral, the margin of the ray being abruptly rounded. In sulu- 

 ensis the spinelets of the exposed surface are lanceolate squamules, 

 while in multicinctus a narrow transverse band is clad with roundish 

 squamiform granules abruptly larger than the other spinelets. In 

 suluensis the inferomarginals extend laterally slightly beyond the 

 superomarginals, and the lateral comb consists of proximally 4 and 

 distally 3 sharp, slender appressed spines. The first 2 or 3 plates 

 may have a rudiment of the second comb, covered by the upper 

 -spines. This is lacking in multicinctus, and the inferomarginals do 

 not extend laterally beyond superomarginals. The plates are wider 

 and the actinal surface more nearly plane than in multicinctus. On 

 the first 8 plates a delicate spinule, spaced from the lateral comb 

 stands on the adoral margin, as in tenuis. (In imilticlnctus this 

 spine is present but larger, and a second may be present on the first 

 3 or 4 plates.) The squamules covering the plates are lanceolate to 

 oval, smaller than in multicinctus, and slightly spaced, not crowded 

 and overlapping. 



The abactinal paxillae are about the same size as in multicinctus. 

 A large paxilla has 15 to 18 peripheral and 8 to 10 central, delicate, 

 terete, spinelets, shorter than the low pedicels. The pediceliariae are 

 distinctly larger than neighboring paxillae and have 4 to 8 pointed 

 jaws, either forming 2 opposing rows, or a circle. There are a num- 

 ber of low paxillae, with spinelets, in addition to the pediceliariae, 

 forming a transition between normal paxillae and the low pedicel- 

 larian plate. In proportion to the ^neighboring plates the pedicel- 

 iariae of suluensis are larger than in multicinctus., in which the 

 pediceliariae are equal to the paxillae, or sometimes a trifle smaller 

 or a trifle larger, but not conspicuously larger. 



Actinal intermediate plates extending nearly two-thirds length of 

 ray, but the outer ones are minute and rudimentary. In multicinctus 

 they extend half the length of ray. The plates bear groups of rather 

 numerous, slender, spinelets, with one enlarged, in the interradial 

 region. Most of the proximal plates adjacent to the adambulacrals 



