238 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



abactinal surface, but becoming a trifle longer on the lateral. Prox- 

 imally 5 or 6 granules can be counted in the length of the plate, this 

 increasing to 9 or 10. In addition, the plate is surrounded by a regu- 

 lar series of considerably smaller granules, and on the outer end of 

 the plate is a slender, sharp, appressed, inconspicuous spine, one- 

 third to one-half as long as the plate, and persisting for two-thirds 

 to three-fourths the length of ray. The base is swollen, and the 

 distal portion abruptly slenderer. Two smaller specimens from sta- 

 tions 5118 and 5363, having R. 66 mm., lack this spine, which is also 

 usually absent from the odd plate and the first 2 or 3 plates of each 

 ray. Terminal plate obovate, granulate. 



Inferomarginals, corresponding to superomarginals, of about the 

 same width in interbrachium, but much narrower on the ray, those 

 of the distal half or third of ray being either slightly wider than 

 long or, in a specimen from station 5537, slightly longer than wide. 

 They are rather evenly arched from the inner to outer margin and are 

 covered with slightly spaced, conical or acorn-shaped granules, a 

 trifle larger than those of the superomarginals, the marginal series 

 being a little smaller and the fasciolar channels very narrow and 

 shallow. The proximal plates have 6 to 10 slender, appressed spines, 

 similar to the superomarginal spines, and scattered from the inner 

 margin to the lateral face of the ray or in 1 or 2 fairly definite series, 

 the number decreasing gradually to 2 to 4 on the outer part of the 

 ray, or 1 in smaller specimens, the last half dozen plates usuallj'^ 

 lacking the spinule. The marginal spines are always appressed flush 

 with the surface of the plate, often lying between the granules. In 

 many cases they taper evenly to a sharp point without being con- 

 stricted about the base. 



Actinal intermediate areas large, the plates elongate, in irregu- 

 lar series extending from adambulacral to marginal plates, and reach- 

 ing distad as far as the ninth inferomarginal of type. Corresponding 

 to the unpaired inferomarginal there are 2 series, the inner end of 

 each abutting against the third adambulacral. Inclosed between 

 the two are a couple of incomplete (short) series opposite the second 

 adambulacrals, these in turn inclosing a longer and incomplete un- 

 ixaired series. The latter is irregular, and proceeds from the meet- 

 ing point of 2 plates, one back of each first adambulacral plate. In 

 the type this unpaired actinal intermediate series reaches to within 

 2 plates of the margin, the outer end being crowded between the 

 outer ends of the 2 series which extend from each third adambulacral 

 to the unpaired inferomarginal. Plates low, and covered with sub- 

 conical, rather irregular, skin-covered granules which become slen 

 derer on drying; and with a central appressed sharp spinule similar 

 to the inferomarginal spinules. 



