The writer has examined nine porpoises and two dolphins collected 1950-1952 along the west coast of North America between southern California and the Pribilof Islands, Alaska. Unless otherwise noted, the skulls are deposited in the U. S. National Museum. In the specimen description the National Museum catalog number is followed by the original field number. Length measurements are from snout to base of tail notch. Gratitude is acknowledged for field assistance offered by James I. Manzer and Tom Bracewell of the Fisheries Research Board of Canada; Ford Wilke, Karl W. Kenyon, Wilfred D. Crabb, Edward A. Schaefers, and Donald R. Orcutt of the U. S. Fish and Wildlife Service; George P. Smith of the Seaside Aquarium, and W. H. Schmidt of the Washington State Department of Fisheries. Stomach contents were analyzed by Delbert G. Goodwin or Ford Wilke, identified as (G) or (W) in the discussions.