266 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 15 



and taper distally to a blunt point ; in cross section they are subcircular, 

 not longitudinally grooved. They are most numerous in the fifteenth 

 segment, where they number about 17 in a single row; they diminish 

 gradually in number to only 4 or 3 in the last thoracic segment. At first 

 they occupy the entire anterior row in a fascicle; in the last thoracic seg- 

 ment they lie only in the uppermost end of the fascicle and are replaced 

 by normal uncinate hooks below. The posteriormost part of the fascicle 

 has stiff pointed setae. The aperture of the glandular pouch is accom- 

 panied by a foliaceous lobe (fig. 2) in front of the uppermost modified 

 spine. 



Branchiae are present from the fifth setigerous segment and continue 

 back to the end of the body ; they are simple, lingulate and fimbriated 

 along their lateral margins (fig. 3). Subpodial or ventral fringe begins 

 as a single paired filament on setigerous segment 12 or 13, located below 

 the ventral edge of the neuropodium. On the next segment the fringe 

 forms a nearly continuous row across the ventrum and is so continued 

 on 15 to 20 segments as a single or partly double row. The fringe is 

 usually absent after the fifth abdominal segment. 



Thoracic neuropodial fringe begins on the first setigerous segment; 

 the number of lobes in a row increases from about 6 on the first, to 12 

 to 14 on the last thoracic neuropodium. The fringe is continued in 

 abdominal neuropodia so that the first may have 5, the second 2 lobes 

 and thereafter it is absent. 



Anterior thoracic neuropodia have setae of two kinds ; one is longer, 

 slenderer and gently curved and is in the posterior part of the fascicle; 

 the other is shorter, thicker and more curved (fig. 4). The spinous 

 region is extensive along the curved part of the seta. Transverse rows 

 of spinelets (fig. 6) are continued around the sides and leave bare only 

 a narrow space (figs. 7 and 8) ; the distal end of the seta is smooth 

 and under high magnification (seen with transmitted light) shows the 

 so-called canaliculations or chevrons (fig. 5) which are internal, not 

 surface structures. 



Aricia macginitii Berkeley and Berkeley (1941) from southern Cali- 

 fornia is here referred to Phylo ornatus (Verrill) since the two agree in 

 characters indicated on the chart above. The only difference, considered 

 nonspecific, concerns the number of segments in the posterior thoracic re- 

 gion. This number differs to an even greater degree in individuals from 

 a single locality, such as North Carolina, where many specimens were 

 taken in a single season. 



