NO. 13 COE : REVISION OF THE NEMERTEAN FAUNA 271 



6. Pale olive brown, grayish ocher, or buff; deeper brown in intes- 

 tinal region, and with a paler median dorsal stripe in esophageal 

 region; 6 to 12 or more small ocelli in an irregular row on each 

 side of head olivaris 



7. Deep red ; sometimes purplish in esophageal region and brighter 

 red anteriorly; head bright red with a narrow, but very sharp 

 and conspicuous transverse band of white just behind tip, with 

 small, dark brown or black spot on exact tip .... nigrirostris 



7. Salmon, gray, flesh color, pale red, or light rosy brown, shading 

 into lighter, with tinges of lighter red or yellow or nearly white 

 anteriorly; intestinal lobes more deeply colored, sometimes 

 brown; a cream-colored stripe often situated in median ventral 

 line alaskensis 



30. Micrura alaskensis Coe, 1901 

 (Plate 24, fig. 12) 



M. alaskensis Coe, 1904, 1905; M. griffini Coe, 1905. 



Habitat. Beneath stones, in crevices of rocks, in sand and sandy mud 

 between tides. 



Distribution. Alaska, British Columbia, Puget Sound to southern 

 California and Ensenada, Mexico; common in many localities. 



Reproduction. Sexual products mature during the warmer months of 

 the year; the eggs develop rapidly as far as the pilidium stage after arti- 

 ficial fertilization. The blastomeres are sharply defined during the spiral 

 type of cleavage, making the egg very suitable for experimental purposes. 



31. Micrura impressa (Stimpson), 1857 



Cerebratulus impressus Stimpson, 1857; M. impressa Coe, 1901, 1904, 

 1905, 1905a. 

 Distribution. Known only from Stimpson's original specimen taken 

 in Bering Strait. 



32. Micrura nebulosa Coe, 1905 



M. nebulosa Coe, 1905a. 



There is a superficial resemblance between individuals of this species 

 and heavily pigmented specimens of M. pardalis, but in the latter the 

 spots or blotches are limited to the dorsal surface. 



Habitat and distribution. An abyssal species at present known only 

 from a single specimen dredged from a depth of about 900 m in the 

 Pacific Ocean south of Alaska Peninsula. 



