ALASKA NEMERTEANS 1 7 



examination of a number of individuals, however, shows that the 

 markings on the body present such constant differences that the two 

 species must be considered distinct. C. capistrata is likewise differ- 

 ent from any of the other related and described species. It may at 

 once be distinguished from C. snperba by lacking all indications of 

 a median ventral white line. The markings on the head and the ar- 

 rangement of the anterior transverse white lines distinguish it easily 

 from C. annulata and C. nothus Burger ; from C. dinema it may be 

 separated by the presence of but one pair of lateral white lines, in- 

 stead of the two pairs found in C. dinema. 



C. capistrata is a very large species, attaining a length of more 

 than a meter with a diameter of about 5 mm. near the anterior end, 

 and of 2 to 3 mm. farther back. The worms are therefore extremely 

 long and slender, and the diameter in the esophagal region is twice as 

 great as it is farther back. The body is strongly rounded on the dorsal 

 surface throughout its whole length ; the posterior end is very slender 

 and easily broken. 



Head broad, flattened dorso-ventrally, rounded or emarginate in 

 front, sharply marked off from succeeding portions by a pair of deep, 

 lateral, transverse constrictions, or furrows. Proboscis-pore minute, 

 subterminal, bounded on each side by a shallow horizontal groove. 

 Mouth small, slightly elongated, situated immediately behind the 

 lateral furrows. 



Color. General color of body rich, deep brown, sometimes vary- 

 ing towards grayish black ; posteriorly becoming lighter, and of a 

 yellowish brown. On this ground color is a series of conspicuous, but 

 fine, longitudinal and transverse white lines (p1. i, fig. 1). The lon- 

 gitudinal lines are three in number and parallel one in the middle of 

 the dorsal surface, the others just ventral to the lateral margins. The 

 dorsal line extends without interruption from near the tip of the head 

 to the posterior end of the body. The lateral lines, on the other hand, 

 are much broken up in the anterior portions of the body, and in the 

 esophagal region are only indicated at intervals, though their course 

 can be followed nearly to the head ; throughout all the rest of the 

 length of the body they are sharp and distinct. 



The transverse white lines, excepting the most anterior one, com- 

 pletely encircle the body. This first transverse line appears as a sharp 

 V-shaped marking a little back of the head. Its angle is directed 

 backward and its extremities reach but little below the lateral margins. 

 The median dorsal line passes through the angle of this V-shaped 

 marking, and at the point of intersection the white area is somewhat 

 Proc. Wash. Acad. Sci., March, 1901. 



