A 16-ft. female beaked whale of the genus Mesoplodon, family Ziphiidae, drifted ashore at Delmar, about 15 miles north of San Diego, California, on June 10, 1954, One of us (R. M. G.) made body measurements, drawings, and photographs of it, and preserved the skull and jaw. The specimen was presented to the United States National Museum where it is catalogued as No. 298237, but was temporarily retained for examination. Because the specimen could not then be identified to species, this material was laid aside and, in the pressure of other affairs, forgotten. After one of us (J. C. M.), in order to revise the genus Mesoplodon, had completed a tour of most museums of the world known to possess specimens, he was invited to investigate this Delmar specimen to include data from it in his revision.