498 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



In addition, there are numerous small forficiform pedicellariae scat- 

 tered among the papulae. The papulae occur in tufts or clumps, 

 about 6 or 7 to each area. 



Adambulacral plates small and bandlike, separated by an interval 

 slightly in excess of their length. Spines, 2, slender, slightly tapered, 

 blunt, situated on the furrow margin in an oblique series, the inner 

 being aboral to the outer and about two-thirds to three-fourths as 

 long; the latter is one-half to three-fifths as long as the inferomargi- 

 nal spine. About every other plate has on the furrow^ face 1 or 2 

 forficiform pedicellariae about 1 to 1.25 mm. long. These extend 

 between the tube feet, and are at the end of a thick, apparently highly 

 extensible stalk or peduncle, around the base of which are 1 to several 

 very small pedicellariae. These pedicellariae have the ends of the 

 jaws crossed and are broader than in volsellatus, where the jaw tips 

 fit together snugly. In the small regenerating rays of a specimen 

 from station 5217 (the tube feet being 2-ranked) the adambulacral 

 plates have 2 truncate, slightly tapered, subequal spines. 



Mouth plates resembling those of the Brisingidae, excavated on the 

 furrow margin for the first tube foot. On the middle of the actinal 

 surface of each plate is a robust, flattened, truncate spine about as 

 long as the median suture. On the actinostomial margin are 2 simi- 

 lar shorter spines, 1 directed across mouth of furrow, the other mid- 

 way to the median suture. From the base of the latter is a short 

 flap of membrane, and from the former are 2 long, slender sacculi 

 crowded with very numerous small pedicellariae. Two large pedun- 

 culate, unguiculate pedicellariae (similar to those of the abactinal 

 surface) extend over the actinostome from between the inner mar- 

 ginal spines of each mouth-pair. Numerous small forficiform pedi- 

 cellariae with short, thick pedicels are scattered over the surface of 

 the plates, and sometimes 1 or 2 major unguiculate pedicellariae in 

 addition. In volsellata there are the same number of spines, but the 

 marginal spines lack the streamers of pedicellariae. The unguicu- 

 late pedicellariae are present, but very few small pedicellariae on the 

 surface of the plate. In the type the first 10 pairs of tube feet are 

 obviously 2-ranked ; then they become crowded and 4-ranked, return- 

 ing to 2 series on the outer attenuate part of the ray. A smaller 

 specimen from station 5217 has the feet less obviously 4-ranked. It 

 is wholly a matter of age. 



In halicepus the disk has more numerous spines^ — about 30 — and 

 more numerous unguiculate pedicellariae. The madreporic body is 

 slightly larger. 



Type.— Cat. No. 37012, U.S.N.M. 



Type-locality. — Station 5281, between Lubang and Luzon, 201 

 fathoms, dark gray sand, bottom temperature 50.4° F. ; 1 specimen. 



