EGYPTIAN TERTIARY VERTEBRATA 68 1 



thoroughly explored — a matter of no very great expense or 

 difficulty. 



The question of the relations of the Ethiopian land-mass to 

 other regions during the Tertiary period is one of great interest. 

 That it is almost certain that Africa and South America were 

 united during the Secondary period has been pointed out by 

 many writers, and there is considerable probability that this 

 union may have persisted till early Tertiary times, though there 

 is considerable difference of opinion as to the position of the 

 connection. It has even been suggested that a belt of shallow 

 water and a chain of islands may have existed between Africa 

 and Brazil so late as the Miocene. This connection between 

 Africa and South America would account for a number of 

 curious facts of distribution, as, for instance, the presence of the 

 Hystricomorphine rodents and the Pelomedusid chelonians on 

 both continents. The occurrence in the Santa Cruz beds of 

 Patagonia of Nccrolestes, a close ally of the Cape Golden Moles 

 (Chrysochloridce), has also been pointed to as evidence of this 

 former union, but this has been considerably discounted by the 

 discovery in the Miocene of North America of Xenotherium, 1 

 an animal which is almost certainly closely allied to the 

 Chrysochloridae, though it was described by its discoverer as 

 probably a Monotreme. 



Some South American palaeontologists have asserted that 

 certain groups of Ungulates found in the Tertiary beds of 

 Patagonia are closely allied to, if not the actual ancestors 

 of, some of the African subdivisions of that order — e.g. the 

 Hyracoidea. There seems, however, to be no real ground for 

 this belief, and it is far more probable that the two continents 

 were separated before the main divisions of the Ungulata had 

 become differentiated, and that such resemblances as do exist 

 are merely the result of parallelism in the course of evolution of 

 the group in the two areas. 



The late Oligocene or early Miocene union between Africa 

 and the Palaearctic continent has already been referred to in 

 connection with the migration of the Proboscidea ; but it is 

 certain that other unions, probably of a temporary nature, must 

 have occurred in earlier Tertiary periods. The presence in 

 both the European and African Eocene of the same genera of 



1 Douglass, " The Tertiary of Montana," Mem. Carnegie Museum, vol. ii. (1905) 

 p. 204. 



