132 BULLETIN 70, UNITED STATES NATIONAL MUSEUM 



The carina! spines are not typically larger than the dorsolaterals although more 

 numerous to a plate, and in some but not all specimens they form an irregular band^ 

 due to greater crowding. The spines do not form conspicuous, often elevated groups 

 «s in Atka and Adakh, and most of Attu and Agattu examples of alaskensis. There 

 arc typically two supermarginal spines, two inferomarginals (on the first three or 

 four plates, one) and a short series of actinals (scarcely reaching the middle of R). 

 The first three or four superomarginals may have three spines, or only one; the distals 

 sometimes have three. The inferomarginals are heavier than the superomarginals, 

 sometimes terete, sometimes slightly clavate. On the outer part of the ray the 

 lower spine is usually heavier than tli3 upper, or the upper two, for three occasionally 

 occur. 



Adambulacral spines one and two, in fairly regular alternation, and very similar 

 to those <>f alaskensis. Three adoral pairs of adambulacral plates are in contact 

 interradially. The oral plates are also similar to those of alaskensis and the outer 

 of the two apical marginal spines is frequently absent. 



The straight pedicellariae (pi. 48, figs. 1, la-Id) are of the common compressed 

 ovate form, and are smaller than the broadly wedge-shaped ones of alaskensis. In 

 some pedicellariae the jaws, as seen from the back or outer side, taper narrowly to a 

 blunt or acute point (fig. la) while in others (usually near the base of ray or in axillary 

 channel) the jaws are untapered, sometimes slightly constricted at the middle, and 

 end in two to four teeth (fig. 16). These are more common in Medni examples, and 

 are intermediate with the pedicellariae of alaskensis. Small ovate and lanceolate 

 pedicellariae occur in clusters on the oral spines, among the crossed pedicellariae of 

 the furrow spines and on the furrow face of the adambulacrals. The latter are the 

 smallest of all. 



Crossed pedicellariae distributed as in alaskensis. They vary considerably 

 in number. 



Madreporic body as in alaskensis, surrounded by a complete circle of spinelets. 



Variations. — It is to be noted that the straight pedicellariae of Medni examples 

 are more variable than are those of Bering Island specimens. Abactinal straight 

 pedicellariae are very scarce outside of the supramarginal channel, and the number 

 of marginal and actinal ones is quite variable. In the arrangement of the abactinal 

 spines there is much less variation than in specimens of alaskensis from Attu and 

 Agattu. The abactinal surface of asiatica resembles that of some stout-spined 

 examples of alaskensis from Kodiak in which the pedicellariae are also narrower 

 than in typical alaskensis from Unalaska westward. The largest specimen, from 

 Medni, has R 62 nun. There are five specimens from Simushir, Kuril Islands, which 

 constitute a distinguishable form (pi. 57, fig. 5), differing from typical asiatica in 

 smaller size, fewer and relatively larger abactinal spines, which do not clearly define 

 papular areas but appear scattered; and in the lateral spatulate pedicellariae of 

 conspicuous si/.e which occur along with ovate conical ones. This may be similar 

 to the ordinary Kamchatkan form, of which there are no specimens. 



Type.— Cut. No. E 1502, U.S.N.M. 



TypeJocaltiy. — Nikolski, Bering Island, shore rocks, June 15, 1906. 



Distribution. — Known from Simushir (Kuril Islands), Bering Island, and Medni 

 Island (Commander Islands). 



