302 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 15 



Transition from thorax to abdomen is after segment 26 or at seg- 

 ments 17/18 (in 2128-52). Thoracic parapodia have thick, tufted 

 fascicles of notopodial setae and longer series of neuropodial setae (fig. 

 6). The uncini are coated with a rust-colored extraneous substance but 

 when cleared of it they are pale amber, as are the other setae. Thoracic 

 notopodia have a long, slender postsetal lobe and long pointed setae. The 

 corresponding neuropodia from the first segment have a postsetal ridge 

 with a long papilla at the middle of the ridge. At the seventh segment 

 there is a second lobe (fig. 6) and this is continued through thoracic 

 segments. In transitional segments the lower one resembles a ventral 

 cirrus (fig. 7). These lobes are absent in abdominal segments. 



Thoracic neuropodia have pointed setae (fig. 3) and ridged uncini 

 (fig. 4). The first one has 2 to 4 vertical rows of uncini, together 

 totaling about 24, located at anterior and superior positions of the fas- 

 cicle; about 15 long pointed setae are located in posterior and inferior 

 rows. The second neuropodium is similar to the first but larger. After 

 the third segment the uncini occupy most of the setal fascicle and may 

 form six to ten vertical rows in conspicuous ranks, with a single posterior 

 row of pointed setae. Uncini are sharply curved and have conspicuous 

 transverse ridges at the outer edge (fig. 4). Seen from the ridged side 

 they are distally truncate to excavate and cuspidate in their subdistal 

 region. 



Abdominal notopodia have a long, slender postsetal lobe, a fascicle 

 of long pointed setae with a few furcate setae (fig. 8) and several em- 

 bedded yellow acicula. The corresponding neuropodia have a smaller 

 postsetal lobe (fig. 8), a more delicate fascicle of pointed setae and one 

 or two yellow acicula that may project somewhat from the parapodium. 

 The furcate setae are about as thick as the pointed setae with which 

 they occur but are shorter, the two tines unequally long and the shaft 

 slightly spinous (fig. 5). 



Dorsal ciliated mounds are visible through most branchial segments 

 as slight circular elevations somewhat in front of the branchial bases 

 (figs. 1, 6, 7). They are widest apart in the thorax and approach medi- 

 ally in abdominal segments. 



Naineris uncinata belongs to the group of species in which thoracic 

 neuropodial setae consist of only pointed setae and uncini. It differs from 

 others in that the neuropodial postsetal lobe is divided in thoracic seg- 

 ments. It is distinguished from nearly related forms in the key above. 



Distribution. — The type collection comes from South Slough, Coos 

 Bay, Oregon, in hard packed sand and eel grass ; others are from Cali- 

 fornia in littoral depths to 340 fathoms (Hartman, 1955, p. 128), and 

 from southern Alaska, shore. 



