ZEtTGLODONTID^. 235 



elongated dorsal vertebrae, referred to as " species major" and said to be similar to the 

 Zeuglodon macrospondylus of J. Miiller ; (2) a smaller form with short vertebrse, 

 resembling the Z. bracJiyspondylus of Miiller and referred to by Dames as "species 

 minor " ; (3) a still smaller species represented only by a few vertebrse, which are said 

 to resemble some vertebrae regarded by Miiller as belonging to a young individual of 

 Z. hracliyi^pondylus, but in the light of recent discoveries may more probably be referred 

 to Z. osiris or a closely allied species. 



Somewhat later Schweinfurth collected on the mainland near Qasr-el-Sagha (see 

 map in Introduction) some further remains, including portions of the premaxillse and 

 a nearly complete ramus of the mandible. These specimens were described in detail by 

 Dames *, who founded upon them, especially upon the mandible, the species Z. osiris. 



Further material, including a fine skull and mandible of Z. osiris, was collected in 

 1902 in the neighbourhood of Qasr-el-Sagha by Drs. Stromer and Blanckenhorn, the 

 former of whom has since published an exhaustive memoir f on these remains, referring 

 most of them to Z. osiris, but some to a smaller form to which the name Z. zitteli is 

 given. This writer also compares the Egyptian Zeuglodonts with those of other 

 localities and discusses the relationship of the group. Dr. Elliot Smith % has given 

 an account of natural and artificial brain-casts from the same region, and concludes 

 that probably two genera were present ; he also discusses the probability of the 

 relationship of the Archseoceti to the true Whales, and considers that on the whole 

 the brain-structure is in favour of the usual classification. Eecently Dr. E. Fraas § 

 has described a skull of extraordinary interest from the bottom of the Lower Mokattam 

 series of Cairo (corresponding with the Wadi Rayan series of Beadnell). This specimen 

 has been made the type of a new genus and species, Protocetus atavus, and is remarkable 

 as combining a skull which is typically Zeiiglodont in general form with a dentition 

 which is practically that of a Creodont. The dental formula is : i. 3, c. 1, pm. 4, m. 3. 

 The premolars and molars have not the peculiar serrated form characteristic of 

 Zeuglodon ; pm. 3, 4 and m. 1-3 have three roots and indications of an inner cusp. 

 There can be no doubt that Fraas is correct in regarding this type as an annectant 

 form between the Zeuglodonts and the Creodonta, but, although the origin of the 

 Zeuglodonts is thus made clear, it still seems to be by no means so certain as that 

 author believes, that they may not themselves be the ancestral forms of the Odontoceti. 



Of the material now to be described the most important is the skull of a Zeuglodont 

 discovered by Mr. H. J. L. Beadnell in beds of the Birket-el-Qurun series, and 



* Palffiont. AbJiandl., n. s., vol. i. (1894) p. 189. 



t Beitr. Pal. u. Geol. Oesterreich-Ungarns u. d. Orients, vol. xv. (1903) p. 64. See also Sitzungs'i. 

 math.-phys. 01. k. bay. Akad. "Wiss. vol. xxxii. (1902) p. 341, and Zeitschr. deutsch. geol. Gesell. vol. 55 

 (1903), Protokolle, p. 36. 



X Proc. Eoy. Soc. vol. 71, 1903, p. 322. 



§ Palseont. Abhandl., n. s., vol. vi. (1904) p. 199, pis. x.-xii. 



2h2 



