NEMERTEANS 



193 



20. LINEUS ALBOLINEATUS sp. nov. 



Pl. XVII, fig. 2. 



Body of moderate proportions for genus, rounded in esophageal 

 region and flattened posteriorly. Esophageal region longer in propor- 

 tion to length of body than in related species. Head short, broad, 

 commonly a little wider than neck, but not distinctly demarcated, 

 often slightly emarginate in front, flattened moderately. Cephalic 

 furrows deep, of moderate length, and, in most states of contraction of 

 head, well separated anteriorly; when strongly contracted, however, 

 reaching nearly to proboscis pore as usual. Mouth small, situated 

 about as far back as posterior ends of cephalic furrows. Proboscis 

 small, with peculiarities as described below. 



Color. General color of body deep chocolate brown or olive 

 brown, with very conspicuous, clearly marked, white or pale lemon 

 yellow stripe extending whole length of body in the median dorsal line. 

 On the head this median stripe widens out to form a broad, pear-shaped 

 white marking (pi. xvn, fig. 2) which is often two-thirds to three- 

 fourths as wide as head. It is broadest, and of ten slightly emarginate, 

 very near the tip of the snout, gradually becoming narrower through 

 about half the length of the head, where it is lost in the dorsal stripe 

 which continues throughout the body. The narrow terminal border 

 lying in front of the white marking on head is paler brown and more 

 reddish than the general color of body. In some individuals a faint 

 reddish line extends from each cephalic furrow backward along the 

 lateral margin of the body. Occasionally this line becomes quite 

 distinct. 



Ventral of same color as dorsal surface. A more rosy coloring 

 marks the position of the brain. Cephalic furrows often marked by 

 a slightly paler, rosy color. Intestinal region inclining toward an 

 olive brown shade. White dorsal stripe very sharply marked, with- 

 out gradation into adjacent color. It averages about one eighth as wide 

 as body, but is rather more irregular and less conspicuous posteriorly. 



Ventral side of head reddish brown ; tip of snout ventrally more 

 distinctly reddish ; mouth reddish inside, lips paler. 



In formalin, and even after imbedding in paraffin, the worms retain 

 their dark brown color with the strongly marked dorsal stripe and 

 cephalic marking as in life. In addition, a pair of narrow lines of 

 light color appear on the lateral margins, corresponding to the faint, 

 reddish lines seen in life. They are continuous with the cephalic 

 furrows, and lie exactly on the lateral margins throughout the body. 



