The collecting expedition to the Fayüm in the Spring of 1906 did not result in the discovery of any striking new forms, but nevertheless a large number of specimens was obtained, some of which add considerably to our knowledge of species already imperfectly described. Of these specimens the most important are: (1) An associated skull and mandible of Palœomastodon wintoni with the upper and lower dentition, including the tusks, in perfect preservation; an atlas, humerus, radius, part of an ulna, and some vertebræ of the same individual were also found, and confirm the determinations that had previously been made from isolated examples. (2) A beautifully preserved mandible of a very young Palœomastodon, probably the same species. In this specimen the two posterior milk-teeth are in position, while the anterior one is represented by its empty alveolus. Beneath the two milk molars are the germs of pm. 3 and pm. 4, almost ready to replace them vertically in the ordinary way.