018 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



plates. Mandibles (fig. 6) frail, dark brown, with lighter dental 

 plate marked by rows of concentric striations. 



trills beginning on twentieth parapodium as a single filament at 

 base of large dorsal cirrus. Increasing rapidly to several filaments, 

 the greatest number being- five posteriorly (fig. 8). 



Anterior parapodia (fig. 7) with large blunt ventral cirrus and 

 large conical dorsal cirrus. Three acicula, two dark brown, one 

 light; all with blunt terminations. Dorsal setae tuft composed of 

 simple capillary setae (fig. 9). Ventral setae tuft composed of three 

 types. First variety (fig. 10), compound with long pointed termina- 

 tion. Second variety (fig. 11), compound with shorter pointed 

 termination. Third variety (fig. 12), compound with bidentate, 

 protected termination. 



Posterior parapodia (fig. S) with small ventral cirrus and more 

 slender dorsal cirrus. Gill, arising from base of dorsal cirrus, so 

 situated as to resemble the digits of a hand. Two setae tufts, the 

 dorsal composed of simple capillary (fig. 9), the ventral of simple 

 capillary and compound (fig. 10). Acicula three; one dark brown 

 with blunt ending, situated between the setae tufts (fig. 13) ; two 

 bidentate (fig. 14), with shield, situated in ventral half of para- 

 podium. 



Collected from station D5301, China Sea, near Hongkong, surface 

 temperature 84°. 



Genus RHAMPHOBRACHIUM Ehlers. 



RHAMPHOBRACHIUM PACIFICA, new species. 



Plate 49, figs. 15-23. 



Type. — Cat. No. 18959, U.S.N.M. An incomplete specimen, 40 mm. 

 in length ; width 12 mm. anteriorly, decreasing to 8 mm. posteriorly. 

 Number of somites, 76. Color dull gray with purple head. 



Head (fig. 15) provided with seven tentacles, the median anterior 

 pair or sustentacula being globose. Antero-lateral pair 3 mm. in 

 length, including basal joint. Postero-lateral pair 3.5 mm. in- 

 cluding basal joint. Median unpaired tentacle broken. Tentacular 

 cirri two,' borne on anterior edge of peristomium, scarcely reaching 

 anterior border of head. 



Jaws (fig. 16) brownish lavender. Maxillae borne on basal piece; 

 curvature moderate. Deeply notched posteriorly and ventrally for 

 ■muscle attachment. Great dental plates notched in same manner. 

 ■Left provided with nine teeth and irregular notch posteriorly ; right 

 with five large teeth. Unpaired plate long, with six large teeth. 

 ^Lateral anterior paired plates dissimilar in shape, with seven and 

 •eight teeth. Mandibles (fig. 17) light brown, with white dental 

 plate anteriorly. 



