66 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 25 



taken with parts missing because cirri and antennae are weakly at- 

 tached. Most characteristic are the distinctly biramous parapodia (PI. 4, 

 fig. 2) with full fascicles of setae, and the pale, nearly uncolored body. 



The prostomium is wider than long, has 3 antennae as shown in PI. 4, 

 fig. 1. The two pairs of eyes are reddish and the two lateral eyes on 

 each side are nearer together than the median distance between either 

 pair. All tentacular cirri are long and cirriform. Segments 2 to 4 are 

 distinct from one another ; each has 2 pairs of long, tentacular cirri, 

 resembling one another ; segment 1 is dorsally reduced. 



Notopodia (PI. 4, fig. 2) have a long, triangular postsetal lobe ex- 

 tending distally slightly beyond the end of the long, slender, tapering 

 pale yellow aciculum. The dorsal cirrus is long, cirriform, extends distally 

 beyond the setal tips. The presetal lobe is somewhat longer and tri- 

 angular. Notopodial setae are of two kinds; the 2 superior are simple 

 and rodlike, and the 4 shorter are farther down, and furcate, with the 

 distal tine very slender and much longer than the shorter tine, which 

 is toothed along its outer edge. 



Neuropodia are longer than notopodia ; they taper distally and have 

 a broad presetal lobe and an equally long, postacicular lobe. Each is 

 penetrated by a straight, tapering yellow aciculum that extends distally 

 to the end of the neuropodium. A supra-acicular fascicle contains about 

 6 long appendaged, tapering composite falcigerous setae (PL 4, fig. 4) 

 resembling spinigers but terminating distally in a delicate bidentate tip. 

 The subacicular fascicle contains about 10 similar composite setae, also 

 with a bidentate tip (PI. 4, fig. 3). The uppermost have the longest 

 appendage and there is gradual decrease to the inferiormost. All neuro- 

 podial setae are of one kind. The ventral cirrus is long, slender and taper- 

 ing. 



Amphiduros is known for two other species (Hartman, 1959b, p. 

 182) both from Japan. They differ from A. pactficus in the details of 

 parapodial lobes and setae. 



Genus Ophiodromus Sars, 1861 

 Type O. flexuosus (delle Chiaje) 1825 



This genus is characterized by having nearly uniramous parapodia; 

 the notopodium is represented by a reduced setal fascicle located on 

 the upper side of the neuropodium. The prostomium is subquadrate, 

 has 3 antennae with the unpaired or median one located at the frontal 



