220 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 46. 



Abactinal plates strongly four-lobed, with a low pedicel, bearing 7 

 to 10 tapering, thorny, pointed spines, the median slightly longer 

 than the peripheral. The spines vary from 1 to 2 mm. in length, while 

 the pedicel is ordinarily about one-half the length of spines. Papular 

 areas of apical region with 5 to 7 papulae; those of proximal part of 

 ray with 3 or 4; those of distal portion of ray with 1 or 2. Counting 

 across base of ray about 18 longitudinal series of plates, rather regular 

 in median radial region. 



Margmal paxillse comparatively small, the superomarginal decid- 

 edly smaller than the inferomarginal and usually alternating with 

 them. The inferomarginal paxill^e have low pedicels, about as high 

 as broad, surmounted by about 15 to 18 spines, of which 3 or 4 on 

 the side toward furrow are about 2.5 mm. long while the others 

 decrease in size to about 0.75 mm. on the dorsal side of the paxilla. 

 The proximal superomarginals have 12 to 15 spines and the pedicel 

 is about two-thirds the height of the inferomarginal pedicels, while 

 the tuft of spines is of about half the bulk of the mferomarginal 

 spines. 



Actmal interradial areas small, the plates bearing 3 or 4 spinelets 

 and extending about two- thirds the length of ray in a single series. 



Type.— Csit. No. 32646, U.S.N.M. 



Type-locality. StSition 5423, Sulu Sea, off Cagayan Island, 508 

 fathoms, gray mud, coral sand, bottom temperature, 49.8° F. 



L. suluensis differs from L. furcifer in having longer, slenderer 

 rays, longer paxillar spines, and relatively shorter pedicels, longer 

 and unequal marginal paxillar spines, more numerous furrow spines, 

 and very much longer subambulacral spines, the latter being longer 

 than the marginal paxillae with their spines. The mouth plates of 

 L. suluensis are larger with more numerous and longer marginal 

 spines (12 or 13). L. suluensis differs from L. stellans Sladen, and 

 L. ahbreviatus Koehler (Antarctic species) in having a much less 

 robust form, longer rays, more numerous furrow spines (4 short ones 

 in stellans and 3 rather long ones in ahbreviatus) and much more 

 prominent subambulacral spines (longer, not shorter, than marginal 

 paxillse with their spines). L. suluensis resembles in general form 2 

 Antarctic species, L. antardicus Koehler and L. gaini Koehler, but 

 differs in having 5 or 6 instead of 4 furrow spines, 12 or 13 instead 

 of 7 or 8 marginal mouth spines. L. antardicus has 20 to 40 paxillar 

 spmes and much less prominent subambulacral spines when com- 

 pared either with the fairly long furrow spines or the more prominent 

 inferomarginal paxillae. L. gaini has more prominent paxillar 

 pedicels, less thorny paxillar spines, more prominent inferomarginal 

 paxillae, and the actinal intermediate paxillse are reduced to about 

 4 in each interradial area. In L. suluensis they extend at least two- 

 thirds the length of the ray. 



