Comments: There is disagreement over the correct specific name. Linnaeus used both macrocephalus and catodon in the 10th edition of Systema Naturae. Leatherwood and Reeves (1983) and many other authors have used the name P. macrocephalus. Recently, Schevill (1986) argued that catodon is the correct name, whereas Holthius (1987) responded that macrocephalus is correct. Jones et al. (1986) stated that the change to catodon was unjustified because it was based on a misinterpretation of the International Code of Zoological Nomenclature. Jones et al. (1992), Baker et al. (2003), and Rice (1998) used P. macrocephalus as the name for the sperm whale. Mead and Brownell (in Wilson and Reeder 1993, 2005) and Nowak (1991) used the name P. catodon.