Fossil Cetacea of New Zealand IV.—Notes on Some of the Bones of Kekenodon onamata Hector By Professor W. B. Benham, F.R.S., F.R.S.N.Z., Hutton and Hector Medallist. [Read before the Otago Branch, September 8, 1936; received by the Editor, October 28, 1936; issued separately, June, 1937.] In the year 1880 the late Sir James Hector described and figured the astonishingly large teeth of the extinct whale to which he gave the above name. He records “that they were obtained from the Upper Eocene strata at the Waitaki Valley in Otago” by A. McKay (1880), of the Geological Survey. The “grinders,” probably molars, are 4 and 5 inches in length, though even these figures do not represent their entire length, as the ends of the roots are broken. They have the general form of crown found in Squalodonts, with the two fangs of the root united for most of their length, and for that reason Hector did not refer the whale to the genus Zeuglodon, but bestowed a new name on the fossil. Kellogg (1923, p. 27) points out the strong resemblance of these teeth to those of Dorudon serratus, which implies a close relationship, and he adds “the character of the teeth places this primitive form with the Zeuglodonts and not with the Squalodonts, as supposed by Hall (1911). In addition to the teeth, Hector figured the tympanic and the periotic bones without, however, giving any description of them, and mentioned that other fragments of the skeleton had been collected by McKay at the same time and place. By the courtesy of Dr. W. B. Oliver, the Director of the Dominion Museum, I have been enabled to examine these other bones, and it seems worth while to put on record the results of my study, incomplete though they are in some respects. Dr. Oliver also was good enough to have photographs and measurements made after I had commenced to study them, and I thank him for his readiness to comply with my various requests in respect of these and other specimens in his charge. It is quite clear from the size of the teeth that the skull must have been very large and heavy, but insufficient material was gathered, and this was so friable that it was difficult to remove it from the rock: and even some of the parts gathered by McKay suffered during the journey to Wellington so as to be useless for any accurate description. Hector indeed mentions fragments of a “massive solid jaw, one portion showing the posterior part of the ramus having a depth of 6–7 inches.” On a later visit to the same area McKay (1881, p. 104) collected further material of four other individuals, which he labelled 2.3.4.5, and they still bear these figures, the original specimen being