234 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



amples. The plates are slightly tumid, arched, and form an evenlj 

 rounded margin to the actinal area, as much, or more, of the plate 

 facing laterallj^ as ventrally on the ray. Plates covered with com- 

 pact granules, subquamiform ventrally. In addition to these the 

 plates of first third or half of ray bear on their inner or lower half 

 or third 2 or 3 short appressed lanceolate spinules, 2 or 3 times as 

 long as the granules, and arranged in a transverse series or in a 

 group, these becoming reduced soon to but a single spinule. Ten 

 inferomarginals at middle of ray correspond to 14 adambulacrals. 



Actinal interradial areas rather small, the plates adjacent to adam- 

 bulacrals much the largest and extending to middle of third infero- 

 marginal. The first plate extends nearly halfway from outer end of 

 mouth plate to inner edge of marginals, about 3 irregular chev- 

 rons filling in this remaining space; no sign of an odd interradial 

 series. Plates covered with papilliform, spaced spinelets, about the 

 length of the inferomarginal granules but less flattened and quami- 

 form. On the interradial suture, between the 2 plates adjacent to 

 outer end of mouth plates, is a fasciolate pedicellaria with 8 to 10 

 shorter, tapering, blunt spinelets in each of the closelj'^ juxtaposed 

 combs. 



Adambulacral plates as wide, or only a trifle wider, than long, 

 with an angular furrow margin, but up to about the fifth the aboral 

 facet of the angle is so much longer than the adoral that the apex 

 is close to the proximal edge of the plate, and the comb of 7 or 8 

 slightly flattened round-tipped furrow spines is largely oblique. 

 Beyond the fifth plate the apex is near but not quite at the middle, 

 and the furrow comb is palmate, the median spines being slightly 

 compressed, while the others are nearly terete or slightly flattened 

 with side to furrow, and decrease in length regularly to the lateral 

 spines, which are only one-third to one-half the length of the mesial. 

 Subambulacral spinelets terete or swollen, blunt, 12 to 15, and in- 

 creasing in length from the outer edge, where they are subequal to 

 the actinal intermediate spinelets, to a row or group of 3 to 5 spaced 

 from the furrow spines and one-half to two-thirds the length of the 

 mesial. Near the outer side of the plate is a stout, sharp, tapering 

 subambulacral spine a little longer than the mesial furrow spine 

 and directed toward the margin. 



Mouth plates narrow, with a prominent angle at mouth of furrow, 

 the margin toward the furrow being concave and having 5 or 6 

 spines decreasing slightly in length toward the angle above men- 

 tioned. The other facet, facing the actinostome, bears 2 or 3 addi- 

 tional spines which continue the series and increase in size to the 

 median, odd, stout, terete, bluntly pointed tooth. About 10 slender 

 terete, blunt spines follow the median suture margin and decrease 

 in length as they proceed outward, the outer 3 or 4 spines sometimes 



