i88 coE 



end of the esophagus forms a strong sphincter between the posterior 

 esophageal chamber (stomach) and the intestine, as described above. 



Blood and Nephr id ial Syste??is. — Cephalic and esophageal lacunae 

 as in related species. Proboscis sheath vessel passes outside rhyn- 

 choccel in the nephridial region, or at about the point where the ante- 

 rior esophageal cavity oj^ens into the stomach. 



The main nephridial canals are of large size, but of limited extent. 

 They are situated beside the posterior fourth of the anterior esophageal 

 chamber, and the anterior third of the posterior esophageal chamber, 

 or stomach. In one small specimen sectioned there was but a single 

 pair of large efferent ducts, while in a larger individual there were two 

 pairs. In the former case the ducts were exactly paired, while In the 

 latter both the ducts on one side were in front of the more anterior of 

 those on the other. 



Nervous System. — Brain and nervous system show no marked 

 deviations from the condition typical of the genus. The frontal sense 

 organ appears to be represented by a crescent-shaped groove above the 

 subterminal proboscis pore. 



Habitat. — In crevices of rocks between tides. Dead Man's Island, 

 San Pedro Harbor; among annelid tubes, breakwater, San Pedro, 

 Calif. ; not very abundant ; one specimen from a floating kelp ' hold- 

 fast 'off San Pedro Harbor (Mrs. Cockerell) ; common among red 

 algae In 50 fms. between San Pedro and Santa Catalina Island. 



The worms belonging to this species are remarkably hardy and will 

 live for more than a day in damp seaweed at a temperature of 70-80" 

 F., and may be kept for a long time in confinement in a small quan- 

 tity of sea water. Sexual products appeared to be fully mature in 

 August, but in some individuals had been previously discharged. 



19. LINEUS PICTIFRONS sp. nov. 

 pi. XVII, figs. 5, 6. 



Body of large size, remarkably soft and flabby, very changeable in 

 shape, but usually somewhat flattened throughout. Body often snarled 

 and tied in knots ; much fluted longitudinally, and constricted trans- 

 versely when contracted. Head narrower than body, elongated, often 

 emarginate in front, narrower at posterior end of cephalic slits than In 

 its middle portion. Cephalic slits unusually long, rosy in color pos- 

 teriorly, sometimes bordered by a narrow line of white. When con- 

 tracted, body is thick, and not flattened, except near anterior end. 

 Posterior extremity rather slender, rounded, not flattened. 



Color. — General color of body, both above and below, deep brown, 



