NO. 1798. CRINOIDS COLLECTED BY THE ALBATROSS— CLARK. 537 



Family ZYGOMETRIDiE. 

 Genus ZYGOMETRA. 



ZYGOMETRA COMATA (A, H. Clark), 



Station 5358. — One specimen with twenty-eight arms 110 mm. long, 

 resembling others from Singapore in the collection of the University 

 of Copenhagen. 



ZYGOMETRA PRISTINA, new species. 



Centrodorsal low hemispherical, the bare polar area papillose, 1 mm. 

 in diameter; cirrus sockets in a single irregular not especially 

 crowded row. 



Cirri moderately slender, XII, 20-21, 12 mm. long; first segment 

 short, the following gradually increasing in length and becoming 

 about one-third longer than broad on the fourth; next two similar; 

 following slowly decreasing in length, the segments in the outer part 

 of the cirri being about as long as broad ; sixth and seventli and follow- 

 ing segments with long sharp dorsal spines; opposing spine nearly 

 as long as the diameter of the penultimate segment, slender, sharp, 

 erect; terminal claw twice as long as the penultimate segment, 

 strongly curved proximally, becoming straighter distally. The cirrus 

 segments are somewhat constricted centrally with slightly expanded 

 and overlapping distal ends. 



Disk covered with rounded isolated flat plates, and thickly plated 

 along the ambulacra and on the anal tube. 



Radials short, about four times as broad as long, sometimes with 

 a faintly marked row of small tubercles along the distal border; 

 IBri about as long as the radials, four times as broad as long, oblong; 

 IBri and ^ united by a pseudo-syzygy in which the outer part of the 

 joint face for about one-half the distance from the periphery to the 

 rim of the central canal is marked with radiating ridges, the space 

 within this border being smooth and flat except for the low and narrow 

 synarthrial longitudinal ridge; IBi^ pentagonal, twice as broad as 

 long. 



Ten arms 50 mm. long; first two brachials subequal, slightly 

 wedge-shaped, twice as broad as long exteriorly; third and fourth 

 brachials (syzygial pair) slightly longer interiorly than exteriorly, 

 twice as broad as the exterior length; next four brachials oblong, 

 slightly over twice as broad as long, then becoming obliquely wedge- 

 shaped, about as long as broad, after the proximal third of the arm 

 less obliquely wedge-shaped, about as long as broad, and terminally 

 slightly longer than broad; the brachials after the tenth have 

 somewhat produced distal ends. Syzygies occur between the third 

 and fourth brachials, again most commonly between the thirteenth 

 and fourteenth, and distally at intervals of from six to ten (usually 

 eight or nine) oblique muscular articulations. 



