MONOGEArH OF JAPANESE OPHIUROIDEA. 339 



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Oral shields rhomboidal, with obtuse inner angle, rounded 

 lateral angles, and widely rounded outer angle ; nearly as wide as 

 long, except the madreporic shield, which is decidedly longer than 

 wide. Adorai shields small, acutely tapered within, where they 

 nearly or hardly meet. Four or five oral papilloo on either side, 

 unequal, short, rounded, but the outermost one, which is closely 

 associated with the second oral tentacle pore, has pointed inner 

 end. Four teeth, short, very wide and stout. 



Arms long and very slender, narrowed at the base, widest at 

 one-fourth to one-third the arm length from the base. Dorsal 

 arm plates mostly triangular, with obtuse outwardly directed apex, 

 rather small, wider than long, successive plates slightly in contact ; 

 quadrangular in the more distal parts. On either side of each 

 dorsal arm plate, occurs a large supplementary plate, which is 

 nearly semicircular, about one-half as large as the dorsal arm 

 plate, and bounded along the distal border by one or two very 

 insignificant secondary pieces, which however are present only for 

 a comparatively short extent. Two or three basal dorsal arm 

 plates and their supplementary plates are smaller than those 

 beyond. The supplementary plates become smaller outwards as 

 the dorsal arm plates become quadrangular, and finally disappear. 

 Lateral arm plates not very prominent, not meeting above or 

 below. First ventral arm plate very small, rather pentagonal, 

 longer than wide. Those beyond quadrangular, with rounded 

 outer lateral angles, truncated inner lateral angles, and slightly 

 notched outer border, about as long as wide, but longer than wide 

 outwards. Three arm spines, short, stout, flattened, slightly 

 tapered, blunt. One large and oval tentacle scale. 



Colour in alcohol : grayish yellow ; disk reticulated, and arms 

 banded, with dark purplish brown. 



