JOHNSON : POLYCHAETA OF PUGET SOUND REGION. 433 
Length of large specimen, 55 mm.; greatest transverse diameter 
of thorax, 7 mm.; of abdomen, 6 mm. 
This beautiful Serpulid is abundant in Puget Sound. Harrington 
and Griffin (’97, p. 103) mention a handsome Serpula, probably 
this species, which forms “hard white tubes ” on the rocky bottom 
of Hood’s Canal; and also as “ whitening the rocks with its calca¬ 
reous tubes,” along the beaches near Port Townsend. It was col¬ 
lected at Alki Point by Miss Robertson. It occurs also on the Cal¬ 
ifornia coast at Bolinas (Duxbury Reef), and at Lime Point and 
Point Cavallo, on the northern shore of the Golden Gate. Its 
favorite habitat is the under side of a stone where the water flows 
freely. If not in a tide-pool, it is near extreme low-water mark. 
The uncini show considerable variation on the same individual, 
and even on the same torus. The number of teeth ranges from six 
to eight; the upper border is high-arched or nearly straight. The 
tip of the large tooth may or may not be recurved. 
The coloration of the branchiae is also variable, both as to tint 
and distribution. It is either scarlet or damask-red, and it may in¬ 
volve nearly the whole of the branchiae and operculum, or may be 
more restricted, so that the white predominates. If formalin speci¬ 
mens are not exposed to direct sunlight the color is retained for 
years in almost its original brightness. 
This may possibly be identical with Serpula jukesii Baird, de¬ 
scribed by Grube (’77) from Xorth Japan. His description is too 
brief, however, to put the question of identity beyond doubt. 
51. Serpula zygophora sp. nov. PI. 19, figs. 205-208. 
Form nearly cylindrical; abdomen strongly grooved on dorsal 
aspect, the somites marked on each side by transverse ridges; seven 
thoracic setigerous somites. 
Branchiae spiral, thirty filaments on each side; carmine-red at 
base, and broadly barred with the same; operculum (Fig. 205) on 
right side, funnel-shaped, moderately cupped, 26-ribbed, the ribs 
extending to the center of the concavity; base yoke-shaped; pedi¬ 
cle long and curved, geniculate just below the operculum; corre¬ 
sponding filament of left side club-shaped. Operculum and pedicle 
variegated with red. 
First setigerous somite .with bavonet-setae (Fig. 206). Thoracic 
uncini six-toothed (Fig. 207); abdominal uncini (Fig. 208) five-or 
six-toothed. Chisel-shaped abdominal setae almost identical with 
those of Serpula Columbiana. Transverse diameter of thorax, 3.5 
mm.; of abdomen, 3 mm. Tube lacking. 
