88 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Superomarginals, 43 to 44 (on longest ray), slightly longer than 

 wide, except at base of ray, and covered with short spinelets, slightly 

 flattened, lanceolate, and blunt on center of plate, slenderer and 

 terete at sides. Each plate on the proximal three-fourths of ray 

 bears, at the upper end slightly aborally from center, a conical sharp 

 spine (as in t&nellus)^ about as long as the plate. Most of the 

 plates bear also, near the center, a low, dome-shaped, fasciculate, 

 pedicellaria composed of 4 to 8 slightly modified stubby spinelets. 

 These pedicellariae are somewhat irregular in position and 2 are 

 occasionally present. Their spinelets are thicker tlian the neighbor- 

 ing spinelets. 



The inferomarginals extend laterally beyond th^ superomarginals 

 defining the border of ray, as in eremicus, lusonicus, and tenellus. 

 Lateral spines 4, or 3 on outer third, slender, tapering, sharp, and 

 sometimes slightly curved ; and, in addition, the plates of the proxi- 

 mal third continue the series to the inner end of plate, with 1 or 2 

 shorter, slenderer, but well-developed spinules. The uppermost 

 spine, or the second, is the longest and proximally equals 2.5 plates. 

 The spinelets of the inferomarginals are coarse, tapering, and bluntly 

 pointed. Most of the proximal plates bear a small fasciculate pedi- 

 cellaria at the upper end, near the base of the first spine ; and on the 

 ventral surface of nearly all the plates are 1 to 3 similar but larger 

 pedicellariae. 



Adambulacral armature: (1) Furrow spines, 3, the median com- 

 pressed and thin, with a rounded, or blunt, point, the laterals a trifle 

 shorter, tapering, and much slenderer. (2) On the actinal surface, 

 back of the furrow series, a series of 2 or 3 spines similar to those of 

 tenellus, the aboral member enlarged, tapering, slender, flattened, 

 blunt-pointed and a little longer than median furrow spine; behind 

 these are 3 to 5 shorter spines. Instead of this arrangement, many 

 plates have the subambulacrals nearly equal and grouped to form a 

 pedicellaria. In this case the spines are especially modified and 

 encircle a pit in the plate; jaws usually 4 to 6. Earely the 2 lateral 

 furrow spines form part of the pedicellaria, there being then only the 

 median left. On some plates simply the outermost 3 or 4 spines form 

 a small pedicellaria. Almost all possible combinations occur. 



Mouth plates narrow, as in the foregoing species. Spines irregular. 

 There are 4 teeth at the inner end of the combined mouth plates; 

 marginal spines small, forming an angular irregular series. Super- 

 ficial spines forming an irregular crowded series along either side of 

 the suture, the outer 1 or 2 of each series being enlarged. 



Actinal intermediate plates few and armed with a fasciculate 

 pedicellaria, with 4 to 6 slender jaws, and with several additional 

 spinelets at the base. 



