204 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



area, the stout, tapering, sharp spine being situated on a slight 

 tumidity at center of plate, and directed horizontally outward. The 

 spines increase in length up to the fourth or fifth, which is about 

 one and one-third times the length of its plate; thence the spines 

 decrease in size gradually with their respective plates. General 

 surface of plate covered with spaced small spinelets similar to those 

 of the paxillae. Sutures between plates prominent and very oblique 

 dorsally. On the interradial suture between the 2 first superomargi- 

 nals is a prominent pectinate pedicellaria (in one interradius 2, one 

 above the other), with sometimes one, also, between the first and 

 second plates of either ray. On the distal third or fourth of ray, 

 between each pair of supero-inferomarginals, is a pectinate pedicel- 

 laria. 



For the distance of the first 4 or 5 marginal plates the ray is 

 unusually thick dorsoventrally. Inferomarginal plates tumid, with a 

 stout lateral spine similar to the superomarginal, and below this 1 

 small spine. On the outer part of the ray the lateral spine is about 

 as long as 2 plates and longer than the corresponding superomarginal. 

 Surface of plates covered with slender, pointed, appressed spinelets, 

 larger, more spaced, and squamiform on the central portion of plate. 

 They are directed away from the inner margin of the plate. 



Actinal intermediate areas small, there being but 2 plates in the 

 series between the mouth and first inferomarginal plates, and about 

 8 for each area, the plates reaching to the middle of the second in- 

 feromarginal. Each area has about 4 very prominent semiovoid 

 pectinate pedicellariae with about 5 or 6 blunt, slightly curved spine- 

 lets in each comb. The plates also bear spaced subequal spinelets 

 similar to those of the inferomarginals. 



Adambulacral plates with a very prominent furrow margin, which 

 touches that of the opposite plate and segregates consecutive pairs 

 of tube feet, the mesial furrow^ spines standing upright, and the 

 lateral usually also. Furrow spines 8 (sometimes T), the 3 or 4 

 mesial terete, untapered, or only very slightly tapered, round-tipped, 

 and upright, similar to the corresponding spines of truUiyes but 

 longer (equaling the plate in length). On either side of these are 

 2 slightly tapered, bluntly pointed spines, the lateralmost the shorter. 

 On the center of the plate is a prominent, upright suboral spine (1.5 

 times length of plate). On the first plate there are 2, and on the 

 distal third of the ray there are regularly 2, the second appearing 

 external to the first, not toward the furrow as in the distal plates of 

 gazellae. Six to 8 spinelets form a series around the remaining 3 

 sides of the plate, usually about 2 standing on either transverse 

 suture margin. 



Marginal mouth spines about 7, which decrease in size from the 

 prominent inner tooth to the third spine, which is only half as long. 



