SABELLIDES AND SERPULIDES 245 



These tubes are much smaller and more fragile than some on shells 

 from Pacific Grove, California, identified as S. asperatus. 



SPIRORBIS ASPERATUS sp. nov. 



pL xxviii, fig. 10; pi. xxx, fig. 4 ; pi. XLI, figs. 4, 5, 6, 8, 10, ix, 19, 31, 32 ; 

 pi. XLIII, figs, i, 2, 3, 7, 13, 26. 



Type locality. Sitka. 



Tubes large, rounded, turning upward in a left-handed spiral, the 

 turns resting one above the other or stretched out, forming variously 

 twisted, crowded masses attached to rocks, shells, and worm tubes ; 

 opaque, yellowish, without lustre, roughened by conspicuous growth 

 lines and sometimes with one to three more or less definite spiral 

 threads. 



Animal long and slender, with 3 thoracic and 16 to 21 posterior 

 segments. Thoracic membrane conspicuous, nearly covering the 

 branchiae. 



Operculum gradually enlarging from the short, stout peduncle, flat- 

 tened dorso-ventrally and protected on the end by a large, thin, cup- 

 shaped calcareous plate having a large, thin, spreading basal portion. 



Superior seta? not differing essentially in form in the three segments ; 

 long, narrow, tapered, finely serrate blades ; in the third fascicle a few 

 with conspicuously fringed ends were found ; as they were not seen in 

 all of the animals examined, it could not be satisfactorily determined 

 whether they simply failed to show in the mounting or actually do not 

 constantly occur. 



Strings of undeveloped eggs in some instances were found along the 

 back of the posterior segments, which were much swollen, each with 

 conspicuous bunches of mucous glands partly concealing the two setas, 

 one of which has the characteristic geniculate form, and the other 

 destitute of a blade, with the end of the shaft or manubrium, pointed 

 and curved. 



Sitka, June 16, very common on rocks and shells, usually associated 

 with bryozoa ; Prince William Sound, at Orca, on Crucigera tubes ; 

 Pacific Grove, California, on small shells. 



SPIRORBIS ABNORMIS sp. nov. 

 pi. xxxix, fig. 35 ; pi. XL, figs, i, 2; pi. XLIII, figs. 24, 28, 29. 

 Type locality. Sitka. 



Dull, opaque, usually rounded tubes in irregular sinistral coils, the 

 whorls often piling on one another, somewhat resemble some forms 

 of S. aspcratus. 



