634 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxvi. 



pressed laterally. There are no dorsal spines; opposing spine sharp, 

 prominent, arising from the entire dorsal surface of the penidtimate 

 joint, equal to about half the diameter of that joint in height; ter- 

 minal claw equal in length to the penultimate joint, stout, and 

 strongly curved. 



Disk with a few rather large plates along the ambulacra, and well 

 plated in the anal area. 



Ends of the basal rays visible as small tubercles in the angles of 

 the calyx; radials projecting slightly beyond the centro-dorsal, gently 

 concave distally; IBr^ and IBro united by syzygy, forming an ob- 

 long syzygial pair from one-third to one-half again as broad as long, 

 the lateral edges straight, barely in apposition basally, the ventro- 

 lateral border slightly produced. 



Five arms, 85 mm. long; first brachial oblong, about three times as 

 broad as long; second slightly wedge-shaped, about the same size; 

 third and fourth (syzygial pair) slightly longer on one side than on 

 the other, half again as broad as the median length; next three 

 brachials approximately oblong, twice and one-half as broad as long, 

 the following becoming triangular, as broad as long, and after the 

 proximal fourtli of the arm wedge-shaped, as long as l)road, and in 

 the terminal portion somewhat longer. The lower brachials have 

 on each side, as far as the lowest pinnule on that side, a slightly 

 produced ventro-lateral edge, corresponding with that on the IBr 

 series; the brachials have a somewhat concave dorsal surface and 

 very prominent distal ends, everted on the proximal, strongly over- 

 lapping on the distal, which gives the animal a curiously ornate ap- 

 pearance. Syzygies occur between the third and fourth brachials, 

 again between the eighth and ninth, and distally at intervals of 

 three, more rarely four, oblique muscular articulations. 



Pc 5.5 mm. long, moderately stout basally, tapering evenly to the 

 tip, rather strongly prismatic, with twelve joints, the first short, the 

 second not quite so long as broad, the third and fourth squarish, the 

 following gradually increasing in length, being nearly or quite twice 

 as long as broad terminally; P^ similar to Pc, with the same number of 

 joints, but somewhat stouter and not tapering so rapidly ; Pa 8.5 mm. 

 long, much stouter than Pc, gradually tapering from the base to the 

 tip with twelve or fifteen joints, the first three about as long as 

 broad, the following verj^ gradually becoming elongated and about 

 twice as long as broad distally; the pinnule is rounded-prismatic; 

 Po similar to Pq ; P?, G mm. long, slender, cylindrical, less stout basally 

 than Pc, gradually tapering and becoming very delicate in the termi- 

 nal portion, with fifteen or sixteen joints, the first short, the second 

 and third about as long as broad, the following gradually increasing 

 in length and becoming nearly or quite three times as long as broad 

 in the terminal portion; P3 similar to P&; following pinnules similar. 



