306 RECENTLY DISCOVERED TERTIARY VERTEBRATA OP EGYPT. 



and therefore since the conditions seem to be very favcffable to the 

 preservation of vertebrate remains, it is to be hoped and expected that 

 many new types of vertebrate life will be discovered, especially when 

 the desert between the Fayimi and the Wadi Natrun can be thor- 

 oughly 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 j^er- 

 sisted till early Tertiary times, though there is great difference 

 of oj^inion 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 che- 

 lonians on both continents. The occurrence in the Santa Cruz beds 

 of Patagonia of Necrolestes^ a close ally of the Cape Golden Moles 

 {C hrysochlorida) ^ 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 Xenotherimri^°' 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, how- 

 ever, 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 jjarallelism in the course of evolu- 

 tion of the group in the two areas. 



The late Oligocene or early Miocene union between Africa and the 

 Palsearctic continent has already been referred to in connection with 

 the migration of the Probosciclea ; but it is certain that other unions, 

 probably of a temporary .nature, must have occurred in earlier Ter- 

 tiary j)eriods. The presence in both the European and African 

 Eocene of the same genera of Creodonts {Hyctnodon^ Pterodon, etc.) 

 and of an Anthracotheroid approximating to Brachyodus^ is evi- 

 dence of this earlier junction. 



The relations of Africa with Madagascar are also interesting. 



a Douglass, "The tertiary of Montana," Mem. Carnegie Museum, vol. ii (1905), 

 p. 204. The writer's attention has been drawn to the fact that Dr. W. D. Mat- 

 thew suggested this relationship some time ago. 



