CBINOIDS OF THE SOLOMON ISLANDS — CLARK. 85 



Cirri xi., 33 to 40, 22 mm. long ; first segment short ; second 

 nearly or quite as long as broad, the following gradually 

 increasing in length to the fifth, which is slightly (sometimes 

 as much as one-third) longer than broad, then remaining uniform 

 up to the tenth or twelfth, from that point gradually decreasing 

 so that the distal segments are about one-third broader than 

 long ; the second and following segments are rather strongly 

 constricted centrally and are provided with strongly produced 

 and overlapping distal ends bordered with prominent spines, both 

 of these characters dying away as the segments become shorter ; 

 after about the tenth segment the spinous overlap dorsally resolves 

 itself into prominent paired spines, which at the tip of the cirrus 

 become close together and are replaced by a single median spine 

 on the antepenultimate segment ; opposing spine large and 

 prominent, triangular, median, about as long as the diameter of 

 the penultimate segment; terminal claw stout and strongly 

 curved, but little longer than the penultimate segment. 



Radials short, but extending well up into the angles of the 

 calyx and entirely separating the bases of the I Br 1 ; these latter 

 are oblong, slightly over twice as broad as long, with a small 

 spinous tubercle in the middle of the distal edge ; I Br 2 broadly 

 pentagonal, half again as broad as long, the lateral edges not 

 quite so long as those of the I Br 1 ; the inferior inner angle of 

 these ossicles is slightly turned outward and coarsely dentate ; 

 the distal edges of the I Br 2 are everted and finely spinous. 



The ten arms are about 70 mm. long ; first brachial slightly 

 wedge shaped, about twice as broad as the exterior length, the 

 interior sides united for about two-thirds of their length, the 

 distal thirds making approximately a right angle with each 

 other ; the distal edge bears a small spinous tubercle in its 

 centre ; second brachial slightly larger, more nearly oblong ; 

 third and fourth brachials (syzygial pair) collectively slightly 

 longer inwardly than outwardly, about as broad as the outer 

 length ; next four brachials oblong, half again as broad as long, 

 then becoming very obliquely wedge-shaped, slightly longer than 

 broad, and somewhat longer in the terminal portion of the arm. 

 The brachials have strongly overlapping and spinous distal edges. 

 Syzygies occur between the third and fourth brachials, again 

 between the ninth and tenth and fourteenth and fifteenth, and 

 distally at intervals of from four to eight (usually five) oblique 

 muscular articulations. 



P B absent; P 1 10 mm. long, stiff and spinelike, with twelve 

 segments, the first two not so long as broad, the third tapering, 

 twice as long as the distal width, the following about four times- 



