A. H. CLAEK : THE CRINOIDS OF THE INDIAN OCEAN. 173 



height and moves anteriorly, on the twelfth and following Ijeing median in posi- 

 tion ; distally the ridge very gradually narrows, becoming finally, on the ante- 

 penultimate, reduced to a sharp median tubercle; opjiosing spine much larger 

 than the spine on the preceding segment, sharp, arising from the entire dorsal 

 surface of the penultimate segment, the apex median in position , equal to about 

 the distal diameter of the penultimate segment in height ; terminal claw longer 

 than the penultimate segment, stout, more strongly curved proximally than 

 distally. 



Radials even with the edge of the centrodorsal , diverging slightly distally 

 lEr, short, oblong, about four times as broad as long, not united basally; IBr^ 

 almost triangular, the lateral edges only half as long as those of the IBr^ twice 

 as broad as long; synarthrial tubercles small, but prominent. 



Ten arms about 80 mm. long, moderately slender: first brachial wedge- 

 shaped, about twice as broad distally as the exterior length, interiorly united for 

 the proximal two thirds, the interior edges widely flaring apart in the distal third ; 

 second brachial about the same size , irregularly quadrate ; third and f ourtli 

 brachials (syzygial pair) slightly longer interiorly than exteriorly, twice as broad 

 as the interior length ; next four brachials oblong or slightly wedge-shaped, about 

 three and one half times as broad as long, then becoming triangular, about twice 

 as broad as long, and after the middle of the arm wedge-shaped, twice as broad 

 as long, and in the terminal portion wedge-shaped, about as long as broad. 

 From the ninth or tenth onward the brachials have rather prominently overlap- 

 ping finely spinous distal ends which very gradually die away in tlie distal third 

 of the arm. Syzygies occur between the third and fourtli brachials, again 

 between the thirteenth and fourteenth to fifteenth and sixteentli (with sometimes 

 an extra one between the fifth and sixth to ninth and tenth) and distally at 

 intervals of from four to six (usually five) oblique muscular articulations. 



P, small and weak, 4"5 mm. to .5(1 mm. long with seventeen segments, the 

 first small, irregularly quadrate, the second wedge-shaped, twice as broad as the 

 proximal (greater) length, the third half again as broad as long, tlie following 

 gradually increasing to the sixth which with the remainder, is about as long as 

 broad ; from the third segment onward a dorsal ridge begins to develop along the 

 median external line of the pinnule, after the seventh becoming a high carina- 

 tion ; the eighth and following segments bear prominent processes on the distal 

 border on the line of this carination, triangular in shape, the apex terminal, 

 arising from the whole exterior line of carination , the distal height being equal to 

 about one half the diameter of the segment: P,^ U) mm. to 12 mm. long, much 

 stouter than P, (by far the stoutest pinnule on the artn) and very stiff, tapering 

 gradually from the base to a delicate tip, with twenty-five segments, th<' first 

 two short, the following gradually increasing in lengtli to the fifth which, with 

 the following, is about as long as broad, at the extreme tip becoming somewliat 

 longer; third and following segments strongly carinate, the fourth and following 

 bearing on their distal edges along this line of carination sharp and prominent 



