NO. 13 coe: revision of the nemertean fauna 273 



Distribution. Alaska, British Columbia, Puget Sound, and southward 

 to Monterey Bay, California. A somewhat similar species, Cerebratulus 

 (Micrura) bellus, was reported by Stimson (1857) from Yezo Island, 

 Japan. 



Reproduction and Regeneration. As in preceding species. 



37. Micrura wilsoni (Coe), 1904 



Lineus wilsoni Coe, 1904, 1905, 1905a; Joubin, 1905. 



Specimens recently collected were each provided with a minute white 

 caudal cirrus, characteristic of the genus to which the species is now 

 assigned. 



Habitat. Beneath stones, in crevices of rocks, on kelp holdfasts, as 

 well as in sandy mud near low-water mark and off the coast to a depth 

 of 35 m or more. 



Distribution. Monterey Bay, California, and southward to the Gulf 

 of Mexico. 



Genus CEREBRATULUS Renier 



Nine species of this genus are known from the North Pacific coast, 

 only one of which has been found in other parts of the world. 



Key to Species 



1. Tip of head whitish both above and below, conspicuously dif- 

 ferent from deeply colored body 2 



1. Tip of head not conspicuously different from body in color . . 3 



2. Body very long and ribbonlike, sometimes attaining a length of 

 more than 2 m ; deep red, except tip of snout, which is yellowish 

 white above and below montgomeryi 



2. Body long and ribbonlike, dark brown or reddish purple, except 

 head, which is white on both dorsal and ventral surfaces, back 

 about }i the length of the cephalic grooves, or sometimes nearly 



or quite to the mouth albifrons 



3. Without distinct longitudinal or transverse markings on body . 4 



3. With conspicuous transverse or longitudinal markings on body 8 



4. Body long and ribbonlike 5 



4. Body comparatively short and broad ; brown or reddish brown, 



darker posteriorly, lighter in ventral median line . . occidentalis 



