JOHNSON : POLYCHAETA OF PUGET SOUND REGION. 429 
Branchiae (Fig. 179) about as long as thorax, dichotomously 
branched twice or thrice in some specimens, in others unbranched ; 
pinnate, radioles slender; 16-30 branchiae on each side, forming a 
spiral of 2-3 turns ; each rachis with 2-10 black eye-spots (Fig. 184). 
Tentacles flattened, lanceolate, about one fifth the length of 
branchiae. 
Fecal groove extending forward along mid-dorsal line of abdomen 
to thorax ; at posterior boundary of thorax passing on the left side to 
mid-ventral line of same, and thence to oral region. 
Peristomium with raised anterior border or “ collarette,” deeply 
notched in mid-dorsal line, and produced into two pointed processes 
adjoining the ventral sulcus. 
Thoracic setae (Figs. 180, 181) begin on second somite; of two 
forms,* winged-capillary and mucronate-spatulate ; the latter more 
numerous, forming a close series towards the torus. 
Uncinigerous tori of thorax dorsal to setigerous tubercles; begin 
on third somite; separated by full width of dorsum; uncini biserial, 
of two sorts (Fig. 182), avicular and dilated-cuspidate; both kinds 
with long manubria; the points directed cephalad. Abdominal setae 
all of one kind (Fig. 185) arising from smaller tubercles, which are 
placed dorsad to the uncinigerous tori. Uncini (Fig. 183) uniserial, 
all avicular, with a shorter manubrium than the thoracic uncini; 
rostra directed anteriorly. 
Tube cartilaginous, translucent, adherent to rocks, piles, etc. 
Length of average specimen (exclusive of branchiae), 95 mm.; 
greatest transverse diameter, 6 mm. Greatest transverse diameter 
of largest specimen at hand, 12 mm. 
Numerous specimens from the Puget Sound region, collected at 
Xeah Bav and in the Port Townsend district by the Columbia Uni- 
versitv Expedition, and at Alki Point and Port Orchard by Miss 
Robertson. It occurs also on the California coast as far south as 
Pacific Grove. 
This species is remarkable for the highly variable aspect which it 
presents, owing to the diverse coloration of the branchiae and the 
differences of shape caused by different states of contraction in 
which it has been killed. If killed within the tube, it is almost per¬ 
fectly cylindrical and often of great length, owing to the impossibil¬ 
ity of expansion within the rigid and tightly fitting tube. The 
longest specimen thus killed (posterior somites lacking) measures 
not less than 150 mm. in length and only 5 mm. in greatest trans- 
