ASTEKOIDEA OF NORTH PACIFIC AND ADJACKNT WATERS — FISHER. 227 



ten to twelve to eacli ray, oacli ])lato with two, and inforomart;inals witli one or two 

 stout conical spines, ami in addition a sino;lc row of pointed mar^'inal fjranulcs. Pedi- 

 cellaiiae, liii!;her than wide and wiili denticulate jaws smaller than those of abactinal 

 sui-face, are scattered here and there, usually on tiie lateral face of the plates. Such 

 pedicellarife do not occur in ty])ical spinona. 



Actinal sui'face with numerous ])e(!icellariiP having liighcr jaws than in leiopclta. 

 A prominent series occurs on the row of intermediate plates adjacent to the adani- 

 bulacrals. The dimensions of these pedicellarise are variable in typical sj/inosa. 

 The actinal gramdes are similar in distribution to those of spinosa, but often (though 

 not always) have several points, or only one point, rather than a simple low conical 

 form. They are, therefore, somewhat similar to those of //. californica. Many of 

 the plates have one or two low thimble-shaped tubercles in the center, in place of 

 pedicellaria'. 



Usually the ailoral furrow spine is the shorter of the two, and both are strongly 

 compressed at the blunt tip. The adoral spinelet is sometimes wanting on the 

 outer part, or along most of the ray. Actinal spine shorter than the longer furrow 

 spine and usually compressed at the base in a ])lane ])arallel to furrow. The outer 

 part of plate is covered with granules. Mouth spines four, strongly compressed, 

 chisel-shaped; usually but one suboral standing near margin, and in line with 

 the marginal spines. 



Type.— Cat. No. 27885, U.S.N.M. 



Type-locality. — Albatross station 4804, off Simushir, Kuril Islands, 229 fathoms, 

 coarse pebbles, black sand. 



Distribution. — Known only from the vicinity of Simushir. 



Specimens examined. — Eight; from ty])e locality four, and from station 4S03, 

 same locaUty, depth, and bottom, four. (Albatross, 1906.) 



Remarks. — This race differs considerably in general appearance from ty])ical 

 spinosa of the North American coast, as the photograph of the type-specimen \\'ill 

 reveal. The actual differences are not great, however, the most striking being the 

 form of the granules, the marginal pedicellariff, and adandiulacral armature. 



Along with these sjiecimens were taken one small and four large e.xamjdes of 11. 

 leiopclta armata. Three specunens listed as kiirilrnsis are ])ossibly hybrids of this 

 race and the typical form of Icurileusis. 



The differences between Iriopelta and l-iirilensis are at once aj)])arent on a com- 

 parison of figures. The latter has nuich higher pedicellariir, heavily spined abacti- 

 nals and marginals, marginal pedicellaria', and compressed, rather sjiatulate furrow 

 spines, not stumpy conical ones. The naked surface of the marginals in leiopclta 

 is also quite different from the condition of fi-iirilcnsis. 



HIPPASTERIA LEIOPELTA FUber. 

 n. 40, figs. 1-4; pi. 58, fig. G. 

 llippaslcria Iciopelta Fisher, Zool. Anz., vol. 35, March 29, 1910, p. 553. 

 Diagnosis. — Rays five. R = 30 mm.; r = 20 mm.; R = 1.5 r. General form 

 stellato-pentagonal to arcuate pentagonal, the latter being usual for small speci- 

 mens, which have R = about 1.4r) r. The longest-rayed specimen has R =81..") mm.: 

 r=I8 mm.; R=1.7 + r. Abactinal jdntes smooth in the middle surrounded by 



