142 BULLETIN lOO, UNITED STATES NATIONAL MUSEUM. 



Inferomarginals projecting slightly beyoimd superomarginals on 

 outer part of ray, and forming a rounded bevel to margin of actinal 

 surface, being about one and one-half times wider than upper series. 

 They are covered with a transverse series of 2 to 5 (usually 2 or o 

 distally, and 2 to 4 proximally) small, flat, lanceolate, sharp, ap- 

 j^ressed spines and numerous shorter, slenderer, slightly flattened, 

 blunt spinelets, which on median line of plate are much longer than 

 those of superomarginals. The spinelets lining the deep fascioles 

 are similar to those of upper series. At the upper end of nearly all 

 the inferomarginals, close to the lower or outer margin of the supero- 

 marginal, is a pedicellaria with 2 (less often 3 or 4) blunt, slightly 

 tapered or often clavate spiniform jaws. These pedicellariae are 

 larger than those of the superomarginal plates. 



Actinal interradial areas fairly large, but rather abruptly narrow- 

 ing at base of ray, along which two series of intermediate plates 

 extend two-thirds of its length, while one series continues nearly to 

 the extremity. Between the first inferomarginal and the second 

 adambulacral the series contains 7 to 9 plates. There is an in- 

 cipient odd interradial series of actinal intermediate plates. Be- 

 hind the m.outh plates there is a pair of plates, and from between the 

 outer ends of these extends an odd series of 2 or 3 plates, the whole 

 being wedged between the inner ends of the series leading from 

 the first inferomarginals to the second adambulacral. The odd 

 series is quite inconspicuous. Deep channels lead from the mar- 

 ginal fascioles to the fascioles between the adambulacral plates, 

 these being separated by single rows of intermediate plates. 

 The marginal and adambulacral plates do not correspond, however. 

 At the base of furrow the latter are slightly more numerous, while 

 in the middle third, the former; distally they correspond. The high 

 keel of the intermediate plates which forms the ridges between the 

 channels is covered with slender, long, terete, or slightly swollen, 

 blunt spinelets directed toward ambitus, and similar to those of inner 

 end of inferomarginals. The channels are not lined with spinelets, 

 as are the marginal fascioles, but they are thickly roofed by terete, 

 delicate spinelets, smaller than those on the exposed edge of the keel. 



Adambulacral plates astropectinoicl, with an acute furrow angle, 

 bearing a compressed blunt saber-shaped spine, and on either side of 

 this, two strongly compressed rather slender blunt spines. Some- 

 times a third is added, making the total 5 to 7. Surface of plate with 

 5 to 7 more cylindrical, slender, blunt spines, one forming a series 

 with the second lateral furrow spines, the rest disposed in about two 

 longitudinal series behind this, the laterals of the first series often 

 standing on margin and making on either side the supernumerary 

 furrow spines. The plates are wider than long, well spaced, with a 



