A. H. CLARK : THE CRINOIDS OF THE INDIAN OCEAN. 125 



times squarish), tiie following gradually decreasing in length, the terminal fifteen 

 or rather more being half again to twice as broad as long ; at about the fifteenth 

 segment dorsal tubercles are developed, at first involving only the distal portion 

 of the dorsal surface, later arising in a slightly convex line from near the prox- 

 imal end, the apex being subterminal ; these tubercles are narrow, laterally 

 occupying only a small portion of the median part of each segment, and are 

 slightly rounded dorsally ; on the last three segments the tubercles become 

 somewhat sharper, more erect, and move to a median position ; opposing spine 

 small (though larger than the tubercle on the preceding segment), blunt, arising 

 from the entire dorsal surface of the segment, the apex median or sub-median in 

 position, in height equal to about one third the lateral diameter of the pen- 

 ultimate segment ; terminal claw somewhat longer than the penultimate segment, 

 rather stout and strongly curved. 



Ends of the basal rays and radials concealed ; IBr, very short and band 

 like ; IBr, short, almost triangular, two and one half times as broad as long ; 

 IIBr 4 (3+4), in apposition laterally, though not laterally flattened; IIBr^ en- 

 tirely united interiorly ; IIIBr 2, rarely 4 (3-f-4) ; IVBr 2, but rarely present. 



Sixteen to twenty-five arms 110 mm. long ; first two brachials wedge-shaped, 

 three times as broad as long exteriorly, the first interiorly united ; following four 

 or five brachials oblong, about four times as broad as long, then gradually 

 becoming wedge-shaped, almost triangular, about three times as broad as long, 

 and less oblique and somewhat longer on the outer portion of the arms. The 

 dorsal portion of the arms is perfectly smooth. Syzygies occur between the 

 third and fourth brachials, again between the thirteenth and fourteenth to 

 twentieth and twenty-first (usually in the vicinity of the fifteenth) and distally 

 at intervals of seven to eleven (most commonly eight or nine) oblique muscular 

 articulations. 



Pd 7-5 mm. long, moderately stout basally but tapering rather rapidly in the 

 proximal half and becoming slender distally, with twenty-five segments, at first 

 twice as broad as long , becoming squarish after the tenth ; the first four seg- 

 ments are strongly carinate, this carination decreasing from this point onward 

 and disappearing after the middle of the pinnule ; P, 13 mm. long, slightly 

 stouter than Pd basally , tapering gradually and becoming slender in its distal 

 third, with twenty-six segments, at first twice as broad as long, becoming squar- 

 ish after the ninth and somewhat longer than broad in the terminal portion : 

 the first seven or eight segments are rather strongly carinate and in addition 

 have a low sharp ridge running along their exterior surface at the base of the 

 carinate processes ; P, similar to P, and of the same length, but the low ridge 

 just described may be traced to about the twelfth segment ; P3 9 mm. long with 

 nineteen segments, .similar to the two preceding pinnules, but slightly less 

 stout ; P^ small, 6 mm. long, tapering rapidly in the proximal half and becom- 

 ing very slender distally, with sixteen segments, which at first are twice as broad 

 as long, becoming squarish about the ninth, and longer than broad distally ; the 



