A MONOGRAPH OF THE EXISTING CRESTOIDS 363 



mentioned are unmodified. The second brachial is about the length of the first, and 

 is slightly wedge-shaped; the distal edge is everted and stands out at right angles to 

 the axis of the arm in the form of an enormous thin rounded or fan-shaped crest with a 

 rounded or broadly scalloped edge, sometimes divided in the middle, which may reach 

 1.5 mm. hi height, or from three to four tunes the greater (outer) length of the ossicle; 

 the proximal outer corner of the ossicle is slightly produced backwards over the distal 

 outer corner of the first brachial, and is scalloped or slightly tuberculated. The pro- 

 duced inner distal angles of the first brachials reach as far as the base of the crest. 

 The third brachial (the hypozygal of the first syzygial pair) is oblong, very short, five 

 or six times as broad as long, and is unmodified. The fourth brachial (the epizygal of 

 the first syzygial pair) is very short, little if any longer than the third (hypozygal), 

 oblong, with the distal border everted and produced into an enormous crest similar to, 

 and nearly or quite as large as, that on the second brachial. The fifth brachial is 

 slightly wedge-shaped, with a crest about half as high as that on the brachial preceding 

 and more irregular. The sixth brachial has a strongly produced and thickened 

 distal edge which is coarsely scalloped. The seventh brachial is slightly wedge-shaped, 

 from two to two and one-half times as broad as long, with the distal edge slightly pro- 

 duced in the direction of the axis of the arm and finely spinous. After the tenth or 

 twelfth the brachials become triangular, about as long as broad, and after four or five 

 more very obliquely wedge-shaped and longer than broad, and distally longer and less 

 obliquely wedge-shaped. Beyond the sixth the brachials are almost smooth, with only 

 slightly produced and finely spinous distal edges. 



PI is about 4.5 mm. long with about 13 segments of which the first two are broader 

 than long with rounded dorsal processes, the third is slightly longer, the fourth is about 

 as long as broad, and those beyond the seventh are slightly longer than broad. P 2 is 

 about 4 mm. long, composed of 12 segments, and is similar to PI but with slightly longer 

 distal segments. The genital pinnules are about 4 mm. long with the fourth, fifth, 

 and sixth segments enormously expanded, roofing over the gonads, which are also 

 protected ventrally by strong calcareous plates of irregular shape; the seventh and 

 following segments are small and slender. On one arm Pj and PZ, as well as the 

 pinnules following, bear gonads. 



Locality Siboga station 122; Celebes Sea (lat. 158'30" N., long. 12500'30" E.); 

 1,165-1,264 meters; stone; July 17, 1899 [A. H. Clark, 1912, 1918] (1, Amsterdam Mus.). 



History. This species is known only from the single specimen dredged by the 

 Siboga at station 122, originally described in 1912 and redescribed and figured in 1918. 



STROTOMETRA PRIAMUS A. H. Clark 



PLATE 31, FIGURE 97 

 [See also vol. 1, pt. 2, fig. 230, p. 188.] 



Strotometra priamus A. H. CLARK, Proc. Biol. Soc. Washington, vol. 25, 1912, p. 81 (description; 

 Siboga station 266); Unstalked crinoids of the Siboga-Exped., 1918, p. 192 (in key; range), p. 

 194 (detailed description; stations 266, 297), p. 275 (listed), pi. 24, figs. 64, 65. 



Diagnostic features. The cirri are slender, all' the segments beyond the second 

 much longer than broad, the longest being nearly three times as long as the median 

 width and constricted centrally; the expanded portion of the genital pinnules is pre- 



