276 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



43. Gerebratulus longiceps Coe, 1901 



C. longiceps Coe, 1904, 1905, 1905a. 



Habitat. Under stones near low-water mark. 



Distribution. At present known only from Yakutat Bay, Alaska. 



44. Gerebratulus marginatus Renier, 1804 



C. marginatus Burger, 1895, 1904; Coe, 1905; C. fuscus Verrill, 1892. 



Habitat. Lives in mud between tidemarks and below to depths of 50 m 

 or more. 



Distribution. This is a typical circumpolar species, its range on the 

 shores bordering the eastern North Atlantic being from Scotland and 

 Norway to the Mediterranean and Madeira ; on the shores of the western 

 Atlantic from Greenland and Labrador to Cape Cod and thence south- 

 ward beneath the off-shore Arctic current ; and in the Pacific from Alaska 

 to British Columbia, Puget Sound, Monterey Bay, and south to San 

 Diego, California. 



Reproduction. A classical species for experimental studies in embiy- 

 ology. 



45. Gerebratulus montgomeryi Coe, 1901 



C. montgomeryi Coe, 1904, 1905, 1905a. 



Habitat. Beneath stones and in mud near low-water mark and below 

 to depths of 160 m or more. 



Distribution. Coast of Siberia, Bering Sea, Aleutian Islands, coast 

 of Alaska, British Columbia, Puget Sound to Monterey Bay, California. 



Reproduction. Sexually mature during the warmer months of the 

 year. Development proceeds to the pilidium stage after artificial fertiliza- 

 tion, but the transformation of the pilidium to the adult form has not 

 yet been described. 



46. Gerebratulus occiden talis Coe, 1901 



C. occidentalis Coe, 1904, 1905, 1905a. 



Habitat. Beneath stones and in mud near low-water mark and below. 



Distribution. At present known only from coasts of Alaska, British 

 Columbia, and Puget Sound. 



