8 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



6 1 . Keels on the elements of the division series with the crest coarsely dentate, that on the IBrj 

 strongly bidentate (southern Japan from the Korean Straits to Sagami Bay; 141[?95]-311 



meters) diadema (p. 18) 



b 2 . Keels on the elements of the division series with the crest straight (from the Philippines to the 



Moluccas and Timor; 183-457 meters) quinquecostata (p. 13) 



a 1 . Proximal and distal edges of the elements of the division series and lower brachials everted and 

 denticulate or spinous; lateral portions of the elements of the division series and lower brachials 

 conspicuously spinous; cirri stouter, the longest segments not more than half again as long 

 as broad. 



6 1 . Elements of the division series and lower brachials with the proximal and distal borders everted, 

 very strongly produced, and lobate or coarsely spinous; brachials as far as the fifteenth or 

 twentieth with a supplementary prominence on each side of the median keel; lateral borders 

 of the elements of the division series and lower brachials with numerous long tubercles or 



spines (Bonin Islands; 183-210 meters) dentata (p. 8) 



6*. Elements of the division series and lower brachials with the proximal and distal borders swollen 

 and irregular but not produced, more or less tubercular, armed with scattered spines; no 

 supplementary prominences on the earlier brachials; lateral borders of the elements of the 

 division series and earlier brachials with a conspicuous development of short spines (north 

 of western Ceram; about 200 meters) snelliusi (p. 12) 



STENOMETRA DENTATA Gisten 



Slenometra denlala GISLN, Nova Acta Reg. Soc. Sci. Upsaliensis, ser. 4, vol. 5, No. 6, 1922, p. 115 

 (description; Bock's stations 55, 56, 59; notes and comparisons), figs. 87-91, p. 112, pi. 1, fig. 7; 

 Zool. Bidrag Uppsala, vol. 9, 1924, pp. 14, 80, figs. 107, 108, p. 87 (synarthrial faces) ; Kungl. 

 Fysiogr. Sallsk. Handl., new ser., vol. 45, No. 11, 1934, p. 20. 



Diagnostic features. The elements of the division series and first two brachials 

 have the proximal and distal edges everted and strongly produced, lobate or coarsely 

 spinous, and the lateral borders with numerous long tubercles or spines; and the 

 brachials as far as the fifteenth or twentieth have a supplementary prominence on 

 each side of the median keel. The 15-20 (usually 20) arms are 60-65 mm. long, and 

 the longest cirri are 25-34 mm. long with 56-76 segments. 



Description. The centrodorsal is cylindrical with the flattened dorsal pole beset 

 with small spines. The diameter of the dorsal surface is 2 mm., and the height of the free 

 part of the centrodorsal is 1.5 mm. The cirrus sockets are arranged in five radial 

 groups, the groups in more or less evident alternating columns, which are separated 

 interradially by bare strips. 



The cirri are XXIV, 74-76, 25-34 mm. long. The first segment is short with 

 a distal collar which, especially ventrally, has a somewhat serrate edge. The second 

 and third segments are twice as broad as long, similar to the first but with a more 

 slightly developed distal collar. The fourth and fifth segments are about as long as 

 broad or a little longer than broad. The sixth-tenth segments are half again as long 

 as broad, slightly constricted centrally. The first-seventh segments have a small 

 ventral spine, slightly projecting in lateral view, because of the collar mentioned 

 above. The eighth-thirteenth (or -sixteenth) segments are smooth, those following 

 with a dorsal spine. The distal segments are from two to three times as broad as long. 

 The dorsal spines are small, distinct, distally curved, their height from one-third to 

 one-fourth the width of the segments. The opposing spine is somewhat stouter, its 

 height equal to half the width of the penultimate segment. The terminal claw is 

 about as long as the penultimate segment. 



