xu INTEODUCTION. 



Gigantophis, &c., were collected from the Middle Eocene beds, and it was arranged 

 to revisit the district for the purpose of obtaining further material. This was done, 

 and resulted not only in the collection of much that was new from the Middle Eocene 

 escarpment, but also in the discovery that the Fluvio-marine beds above were bone- 

 bearing and in the finding of the first traces oi Palceomastodon. Towards the end of 

 the same year Mr. Beadnell returned to the district and paid special attention to the 

 Fluvio-marine beds, from which he obtained the first remains of Arsinoitherium, as 

 well as of other new mammals and reptiles ; he was also fortunate in finding a spot 

 where bones occur in considerable numbers in a limited area, instead of being widely 

 scattered as is usually the case in these deposits. His expeditions in the winters 

 of 1902-3, 1903-4, resulted in the accumulation of a very large mass of material 

 (only part of which is here catalogued) in the Geological Museum at Cairo. During 

 the springs of 1902 and 1903 the present writer also collected in the same district, and 

 obtained a considerable number of specimens, including several new forms. Lately 

 Baron F. Nopcsa visited the Fayum and made a collection of vertebrate remains, 

 including some good specimens which he presented to the British Museum : these 

 are referred to in the present Catalogue. In the early part of 1902, Drs. Stromer 

 and Blanckenhorn also made a short stay in the district, and their collections of 

 vertebrate fossils have been in part described: the Zeuglodonts (38, 40, 41) and 

 fish-remains (43, 44) by Dr. Stromer himself ; the Chelonians by Dr. Reinach (34); 

 while Dr. O. Abel is preparing a memoir on the Sirenia, including also the earlier 

 forms from the Mokattam Hills (see also i). 



The collections of remains now preserved in the British Museum and in the 

 Geological Museum at Cairo comprise representatives of all the main divisions of 

 the vertebrate phylum except the Amphibia. Both in point of numbers and interest, 

 the Mammals are by far the most important ; next to these come the Eeptiles, while the 

 Birds are represented by mere fragments of a single species. 



The Mammals may be divided into three sections : — (1) the land-mammals which 

 seem to be truly endemic to the Ethiopian region ; these occur both in the Upper and 

 Middle Eocene beds, and include such genera as Mceritherium, Paloeomastodon, 

 Arsinoitherium, JBarytherium, Megalohyracc, Saghatherium, and perhaps Geniohyus: 

 (2) forms of which close allies occur in other regions in approximately contemporary 

 deposits ; these, so far as at present known, occur only in the Upper Eocene beds, 

 and include such genera as Ancodon, Bhagatherium, Hycenodon, Pterodon, Apterodon, 

 and Sinopa: (3) the aquatic mammals so far not found in the Upper Eocene beds, 



