INTRODUCTION. 
xii 
(/ if/ai/foj)h/s. See., wcic collected from the Middle Eocene beds, and it was arranged 
1o rc'visit the district for the ])urpose of obtaining further material. This was done, 
and r('snlt('d not only in the collection of much that was new from the Middle Eocene 
('scar))ment, hut also in the discovery that the Eluvio-maiine beds above were bone- 
Ix'ai'ing and in the finding of the first traces of Palceomastod on . Towards the end of 
the same year Mr. Beadnell returned to the district and paid special attention to the 
Iduvio-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 tinding a spot 
Avhere 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 Avinters 
of lOOll-o, 1903--4, residted in the accumulation of a very large mass of material 
(only part of Avhich is here catalogued) in the Geological Museum at Cairo. During 
the springs of 1902 and 1903 the present Avriter also collected in the same district, and 
obtained a considerable number of specimens, including several ncAv forms. Lately 
Baron E. Nopesa visited the Eayiim and made a collection of vertebrate remains, 
including some good specimens Avhich he presented to the British Museum : these 
are referred to in the present Catalogue. In the early part of 1902, I)rs. Stromer 
and Blanckenhorn also made a sliort stay in the district, and their collections of 
Aertehrate fossils have been in part described: the Zeuglodonts (38, 40, 41) and 
fish-remains (43, 44) by Dr. Stromer himself; the Chelonians by Dr. lleinach (34); 
Avhile 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 noAv preserved in the British Museum aud in the 
Geological INluseum 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 inost important ; next to these come the Ileptiles, Avhile the 
Birds are reju’esented by mere fragments of a single species. 
The Mammals may be divided into throe sections : — (1) the land-mammals Avhich 
seem to be truly endemic to the Etlho])ian region ; these occur Ijoth in the Ujiper and 
Middle Eocene beds, and include such genera as MoerUhcrinnf, ]\da’oniasto(lon, 
ArsinoifJienvtn, Jlaryihcyivnn, Megaloliyya.v, iSr/f/Iiatheyiiun, and ])erhaps Geniohyus: 
(2) forms of Avhich close allies occur in other regions in approximately contem})orary 
deposits; these, so far as at present knoAvn, occur only in the Upper Eocene beds, 
and include such genera as Ancodon, Jdnu/at/iey/nin, J/ywiiodon, lieyodon, Aplerodon, 
and Siiwj)a : (3) the acpiatic mammals so far not found in tlie Upper Eocene beds, 
