166 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



stomach has comparatively few ciliated cells and the nuclei of all 

 are far removed from the surface. The cells are all very slender, 

 and are thickly packed with small granules of secretions. The free 

 surfaces of the cells are irregular and covered M'ith the secretion 

 which partially fills the lumen of the esophagus, so that it is often 

 difficult to determine exactly where the cells terminate. The 

 ciliated cells of the esophagus proper, on the other hand, always 

 show distinct fi-ee borders. 



Stomach is fully four times as long as esophagus, and at its pos- 

 tei'ior extremity enters the broad cavity of the intestine, which is 

 provided with the usual lateral diverticula and exhibits the usual 

 histological features. The transition from stomach to intestine is 

 very abrupt both anatomically and histologically. 



Blood vessels nearly as in related species. Rhynchocoel vessel 

 very short, leaving cavity of proboscis sheath in the immediate 

 vicinity of the nephridial pores. 



Nephridia remarkably short, but with rather large branches ; 

 extending from near the mouth through anterior fifth of esophageal 

 region only. The two longitudinal canals swell out posteriorly into 

 comparativelj^ large chambers, from which the single pair of efferent 

 ducts pass to the dorso-lateral surfaces of the body. 



Cerebral sense organs well developed, closely united with pos- 

 terior surfaces of dorsal ganglia. 



Habitat.— A few specimens of this beautifully colored species 

 were found on piles at San Pedro, Cahfornia. The species occurs 

 also at Monterey, California, but is not common. 



18. Lineus flavescens Coe. 

 Harriman Alaska Expedition, 11, p. 184, PI. 17, figs. 3, 4, 1904. 



PI. 3, fig. 30. 



Body of moderate proportions ; head long and rather slender, 

 usually a little narrower than body, often pointed, and often 

 slightly emarginate in front ; cephalic slits longer than in most 

 related species ; esophageal region rounded ; intestinal region only 

 moderately flattened ; posterior extremity rather slender, without 

 caudal cirrus. 



