NEMERTEANS 175 



Ventral side of snout pure white, continuous with the white of the 

 margins of dorsal surface, but this color does not commonly extend 

 posteriorly to the snout. Occasionally, however, the white area ex- 

 tends back on the ventral side of the head proper, and may include 

 the mouth region also. Back of snout the ventral color usually be- 

 comes gradually reddish, so that a pale red area generally surrounds 

 the mouth (pi. xvi, fig. 2). 



Ventral surface of esophageal region of a brownish red color similar 

 to that of dorsal surface, but of a much paler and more grayish shade. 

 A much paler grayish median band is often found throughout the 

 whole ventral surface. In intestinal region there is a similar pale 

 brownish red color much influenced by the grayish color of the median 

 intestinal canal and its lateral diverticula. These latter are conspic- 

 uous when the body is well extended, and add largely to the grayish 

 effect of the ventral side of the whole intestinal region. Sometimes 

 ventral surface is of the same brownish red color on the lateral mar- 

 gins as occurs on the upper side of body, but toward the middle line 

 becomes much grayer and paler, while a median line of pure gray 

 extends through the intestinal region. 



The tissues of body in intestinal region show a general salmon or 

 orange color when cut. 



Size, A large species, individuals often measuring 40-60 cm. in 

 length and S-io mm. in width when extended. One of the preserved 

 specimens still measures 20 cm. in length, and 5-7 mm. in width in 

 intestinal region, and 12 mm. just behind mouth. When strongly con- 

 tracted the body of a large individual may become but 68 cm. long, 

 but is several times as thick as when extended. 



Ocelli. On each antero-lateral border of head is an irregular 

 cluster of numerous minute ocelli. When cleared in cedar oil these 

 appear distinctly as an irregular longitudinal row of forty to sixty or 

 more small pigment spots just ventral to the dark head shield (pi. 

 xvui, fig. 6). 



Proboscis. Proboscis sheath possesses an unusual length, extend- 

 ing backward throughout the greater portion of the intestinal region. 

 Proboscis of large size, with two well-developed muscular layers 

 internal longitudinal and external circular as usual. 



Body Walls. The three muscular layers are massively developed 

 throughout the body. 



Cephalic glands are enormously developed, as in most related 

 species, and extend backward into the esophageal region. In front of 

 the brain they encroach largely upon the muscular and connective 



