268 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



Habitat. Beneath stones and in crevices of rocks and corals. 



Distribution. Mediterranean and Black seas; west coast of Africa. 

 Collected by the Allan Hancock expeditions at the following localities: 

 La Paz and San Gabriel Bay, Espiritu Santo Island ; Puerto Refugio, 

 Angel de la Guardia Island ; and at a depth of 30 m off San Francisquito 

 Bay in the Gulf of California; at Ensenada de Francisco, Sonora, and 

 Tenacatita Bay on the west coast of Mexico; and at Secas Islands, 

 Panama. 



25. LIneus pictifrons Coe, 1904 



L. pictifrons Coe, 1905, 1905a, 1932, 1934. 



Habitat. In crevices of rocks, beneath stones, among algae and other 

 growths on rocks and piers exposed to surf, also in mud of harbors and 

 bays, as well as among kelp holdfasts. 



Distribution. At present known from Puget Sound, Monterey Bay, 

 and southward to the Gulf of California. 



Regeneration. This species is of interest physiologically because it 

 shows an intermediate regenerative capacity between such forms as L. 

 ruber, in which the organizing center for anterior regeneration is limited 

 to the region adjacent to the cerebral sense organs, and those like L. 

 vcgetus, in which the organizing center extends the entire length of the 

 nerve cords (Coe, 1932, 1934). 



26. Lineus ruber (O. F. Muller), 1771 



/.. sanguineus Mcintosh, 1873; L. sanguineus, L. viridis Verrill, 1892; 

 L. ruber Stephenson, 1911; Southern, 1913; Wheeler, 1934; L. 

 viridis Cot, 1901, 1904, 1905. 



Habitat. Beneath stones and among shells, grasses, and other growths 

 between tides and below in both sandy and muddy situations. Endures a 

 wide range of ecological conditions in protected bays as well as on the 

 open coast. Survives great changes in salinity. 



Distribution. Circumpolar; Siberia, northern coasts of Europe, Medi- 

 terranean, Madeira to South Africa; Greenland to southern New Eng- 

 land ; Alaska to Monterey, California. 



Remark. This is a classic species for studies on physiology, embryology 

 and regeneration. 



