318 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



slightly where it joins the plate. On the upper surface of the second 

 or third to sixth or seventh plates is a small flat granule correspond- 

 ing to the inner or dorsal spine of the first plate. One superomar- 

 ginal has a lateral, broadly spatulate, pedicellaria. The plates are 

 bordered by a single series of small elongate granules, similar to those 

 bordering the abactinal plates, but longer. Terminal plate large 

 and subglobular with 5 conspicuous tuberculate terminal spines, 

 arising from bosses on the plate. These spines are longer than the 

 distal superomarginal spines. 



Inferomarginals less timid than the superomarginals, with two 

 tubercular spines slightly shorter than the superomarginal spines, 

 in a transverse series. The upper or outer spine is proximally a 

 little longer than the low^er, but beyond the middle of ray is reduced 

 to a small tubercle which is even lacking on the last two or three 

 plates. The inner or low^er spine retains its length to near the end of 

 the ray, where it becomes rapidly shorter. These spines are either 

 directed outward at a right angle to the body or bent toward the tip 

 of ray. A small but variable number of plates bear laterally or 

 ventrally a very broadh- spatulate pedicellaria, and all are bordered 

 by small elongate granules. The first plate usually, and the second 

 plate exceptionally, has a tubercle or a granule, or two to four on 

 the ventral surface. 



Actinal intermediate plates unequally 4-sided, in 3 chevrons, the 

 plates reaching along ray, to the fourth inferomarginal and bear- 

 ing 1, or sometimes 2, heavy cjdindrical blmit spines, sometimes 

 slightly flattened at the tip, a trifle slenderer than, but fully as long 

 as, the longest inferomarginal spines. The plates are bordered by 

 small granules similar to those of the marginal plates, but a little 

 shorter. The free edge is convex or subtruncate. The spines are 

 carried on a slight elevation or boss of the plate and at the base of 

 the spine is a broadly spatulate pedicellaria, similar to those of the 

 marginal and abactinal plates. The jaws are as wide as long dis- 

 tally, and hollowed out, while proximally they narrow abruptly. 



Adambulacral plates a little wider than long, with a slightly con- 

 vex furrow margin, bearing a palmate series of 5 to 7 very unequal, 

 rather slender, blunt spines, sometimes slighth'' compressed, with the 

 narrow side to furrow, or again with the broad side thereto. The 2 

 or 3 median spines are the longest, while the 2 laterals on either 

 side are successively shorter, all being bound together at the base 

 by membrane. The lateralmost spinelet is usually very short. In a 

 transverse series on the slightly convex actinal surface of the first 

 13 to 18 plates are 2 blunt or truncate heavy spines like those of the 

 actinal intermediate plates; beyond the thirteenth to the eighteenth 

 plates there is but one spine. At the base of the furrow the inner 

 of these 2 spines is slightly the larger and scoop-shaped at the tip. 



