144 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



In the anterior portions of the esophageal region are three pairs 

 of longitudinal blood vessels, of which one pair represents the main 

 lateral vessels and lies beside the esophagus, a second pair lies 

 beside the proboscis sheath, and the third pair is situated internal to 

 the ventral wall of the proboscis sheath and projects freely into the 

 rhynchocoel. 



But a single species of this uncommon but widely distributed 

 genus is as yet known from the Pacific coast, and only three species 

 have been found in other parts of the world. The latter are C. 

 armandi Oudemans, from the coasts of Europe, C. patagonica 

 Biirger, from the Straits of Magellan, and C. tremaphoros C. B. 

 Thompson, from New England. 



9. Carinoma mutabilis Griffin. 

 Ann. New York Acad. Sci., 11, p. 204, 1898. 



Carinoma griffini Coe, Proc. Wash. Acad. Sci., 3, p. 20, 1901. 

 Carinoma mutabilis Coe, Harriman Alaska Expedition, 11, p. 115, 

 1904. 



PI. 12, figs. 76-80; PI. 13, figs. 81, 82; PL 14, figs. 83-87; PI. 



15, figs. 88, 89. 



This interesting species can be distinguished from the other 

 nemerteans at present known from the Pacific coast by the above 

 generic diagnosis, and especially by the slender body, rounded 

 antei'iorly and much flattened towards posterior extremity, which is 

 remarkably broad and flat ; head rounded or emarginate in front, 

 wider than neck ; color pure white anteriorly, with cream-colored or 

 brownish intestinal region. The worms often show a tendency to 

 coil the posterior portions of the body in a spiral. 



There is very great variation in size, small individuals being 

 scarcely more than 25 mm. in length, while the largest specimen 

 recorded measu^red more than half a meter Avhen fully extended, 

 with a diameter of but 8 to 5 mm. On the Cahfornia coast few 

 individuals were collected which were above 20 cm. in length, 

 while the average size was much less. 



Griffin ('98, p. 204) describes considerable variation in size, form. 



