INTRODUCTION. 
XXV 
spread to their present habitats, the genus becoming extinct elsewhere, though it 
])crsisted in Egypt till the Miocene. 
The Ophidia are rc])rescntcd by two genera only : one Gigantoijlds, a Python of very 
large size, the other Pterosplienus, of which one species, P. scJiioeinfartld , is found in 
the Payum, while another, P. schuch.erti^ occurs in tlie Eocene of Alabama ; in both 
localities remains of Zeuglodonts arc abundant in the same beds, a circumstance which, 
coupled with the peculiar structure of the vertehrie, shows that these Snakes were 
aquatic and probably marine. Nevertheless, it does not seem likely that they would 
cross oceans of great width, and their presence in Egypt and in Alabama seems to be 
an argument in favour of the presence of a shore-line across what is now the Atlantic 
Ocean, probably lying somewhat to the south. The presence of primitive Sirenians in 
Egypt {Eotherium) and the West Indies {Prorastoinus) is explicable on the same 
grounds. 
No Amphibia have yet been found, and the Fishes are of no great interest, being all 
either Elasmobranchs or Siluroids : among the former occur several types of Sawfish, 
while the latter are chiefly remarkable for their great similarity to forms now living in 
the Birket-el-Qurun and the Nile. 
From the above summary of the contents of this Catalogue, it will be seen that 
a very considerable number of early Tertiary Vertebrates, especially Mammals, are 
already known from Egypt, and that practically all of them have been discovered 
since the beginning of 1900, so that, although Professor Osborn writing in that 
year could say of Africa with truth, “It is the dark continent of Palaeontology, for 
it has practically no fossil mammal history,” this reproach is at least in a fail- 
way to be removed. At present, of course, the species known must be a mere 
fraction of the faunas inhabiting the Ethiopian region during . the Middle and 
Upper Eocene periods, but the proportion of peculiar types included in them 
is great enough to show how fully justified the writers above referred to were in 
their assumption that the Ethiopian continent in early Tertiary (and perhaps 
pre-Tertiary) times was a very important centre of mammalian evolution. 
The question of the relations of this Ethiopian region to the rest of the world is one 
of very great interest. The probability of a series of temporary land-connections 
between it and the Palaearctic continent has already been referred to above and has 
been fully discussed by Osborn, Stehlin, Tullberg, &c. ; in all cases so far as known 
these connections occurred during the Tertiary period. Furthermore, the probability 
of a former land-connection with South America has been argued with much force by 
