436 THE ANNELIDA POLYCHAETA. 



and undivided branches ; a scar proximad of them probably represents a fourth 

 branch that has been broken off. 



There is a pair of conspicuous segmental papillae on each somite from the 

 third to the eighth inclusive. The first ones he each on caudal border of somite 

 between the level of the branchia and the notopodium. The others descend 

 in position ventrad in going caudad, the second and third ones lying between 

 notopodia of adjoining somites, the others ventrad of the notopodia. 



There are the normal seventeen setigerous somites. The ventral plates 

 remain of essentially the same length throughout and decrease in width but 

 moderately caudad. Each is marked off by sulci into a double transverse 

 series of subquadrate areas. 



The notopodia are short. The cross-section at the base is oblong or nar- 

 rowly elliptic, with the long axis dorsoventrad. Distally each is compressed in 

 the anterocaudal direction. The distal edge is obhque, the upper angle being 

 farthest extended. The uncinigerous tori of the abdomen are, in the anterior 

 region of the abdomen, low, with the dorsoventral length long. Caudad they 

 become shorter in the dorsoventral direction and longer from the base distad. 



The notopodial setae are stoutest at base and distally finely pointed. The 

 distal half is narrowly bilimbate. The shafts throughout are finely fibrillate. 

 (Plate 79, fig. 4). 



The thoracic uncini form the usual long, straight series between notopodia 

 and ventral plates. They first occur on the fifth somite. On somites from the 

 fifth to the tenth, inclusive, the uncini appear to be arranged in a single series, 

 whereas in all succeeding ones of the thorax the series is clearly a double and 

 completely interlocking one. On the abdominal tori the series are single. The 

 uncini of the thoracic region are squat in form, with but a single transverse row 

 of usually few teeth above the principal tooth, or fang. The opposite end is 

 narrowly rounded, not prolonged. The shoulder on the convex side is angular. 

 At the middle of the opposite side there is one obtuse angular projection. (Plate 

 79, fig. 5). The uncini of the abdominal region, in general, are similar, but 

 there may be two series of teeth above the fang, and the opposite end of the 

 uncinus is moderately prolonged and narrowly acute. (Plate 71, fig. 6). 



Locality.' Galapagos, 4 miles S. E. of Hood Island: Sta. 4642 (lat. 1° 

 30' h" S., long., 89° 35' W.). Depth 300 fms. Bottom of broken shells and 

 Globigerina ooze. Bottom temp. 48.6° F. 7 November, 1904. One specimen. 



