558 PROCEEDINGS OF THE ACADEMY OF [Julj, 



setffi with miicronate tips and the broad blades curved and often 

 slightly asymmetrical (fig. 3). Abdominal setse are all capillary with 

 the shaft bent at the widest portion of the short double asymmetrical 

 blades. They are arranged in two vertical rows, those in the anterior 

 (fig. 2) having very long, attenuated, smooth tips, the posterior much 

 shorter but otherwise similar. Their number varies from 24 in ante- 

 rior to 4 or 5 in posterior fascicles. All setae are distinctly striated. 



Thoracic tori bear avicular uncini in the posterior and pick-shaped 

 setse in the anterior rank, the number of each on somite VI being 65 

 and on IX 40, The former (fig. 4) have a rather long slender base, 

 narrow but prominent breast, thick erect neck, and little expanded 

 head, with the prominent, finely divided crest pushed well forward and 

 its frontal margin forming a perfectly straight profile with the acute 

 beak, which is just perceptibly bent forward at the tip. On the pos- 

 terior thoracic somites the uncini are somewhat larger, but the differ- 

 ence is not so great as in P. occelata and P. intermedia; the neck is also 

 more craned forward and there are other slight peculiarities. The lat- 

 ter (figs. 6 and 7) have slender, finely striated stems slightly curved near 

 the end, and expanded into a coarsely striated head enclosed in a sheath 

 inflated at the base, and prolonged nearly at right angles to the stem into 

 a moderately elongated slender process. Abdominal tori contain 

 avicular uncini only (fig. 5), smaller than the thoracic uncini which they 

 resem.ble in many respects, but have much the form of the wooden 

 decoys used in duck shooting. 



Except for the caudal eyes, the minute spots at the ends of the tori 

 and a trace of brown on the median dorsal portion of the collar, no 

 pigment exists on the bod}'', which is of a pale yellowish color. On one 

 specimen the basal half of the branchial wreath has no pigment, but 

 in the distal half are four partly coalescent bands of brown, not extend- 

 ing on to the back of the stems, but deep-colored on the sides of the 

 latter and the basal half of the barbs. Wlien the branchise are opened 

 up the barbs of the concealed branchiae are found to be of a beautiful 

 orange in those parts from which pigment is absent. The second speci- 

 men has very little pigment showing on the exterior except narrow 

 longitudinal streaks of brown on the branchial base corresponding with 

 the intervals between branchiae. When opened up the distal half of 

 the branchiae shows traces of orange on the barbs, while the basal half 

 is of a nearly solid orange brown. 



The tubes are rather thick, tough and horn l^rown, and are thickly 

 covered with fine sand; the free end is collapsible for a considerable 

 distance. 



