372 ORIGIN OF LIFE IN AMERICA 



Argentina. It seems manifest, therefore, that the ancestral 

 members of this sub-family have travelled along the west 

 coast of South America probably from a southern centre of 

 dispersal. We find no trace of them in Central America or , the 

 Antilles, but it is in North Africa where we meet with 

 Ctenodactylus with its peculiarly modified inner toes. Here 

 in the Mediterranean region, and not in Africa proper, must 

 have been the Old World centre of dispersal, for we find the 

 allied extinct genus Pellegrinia in the Pleistocene of Sicily, 

 and Ruscinomys in the Pliocene of southern France. A 

 recent relation of Ctenodactylus (Massoutiera) has passed 

 southward towards the Senegal. The main branch, however, 

 has apparently invaded eastern Africa from the Mediterranean 

 region, giving rise to the genera Pectinator, Thryonomys and 

 Petromys. Only a single species (Thryonomys swinderianus) 

 has gained the west coast of Africa. Of the sub-family 

 Echimyinae, which largely inhabits Brazil, Africa possesses 

 no near relations. The only African family of the hystrico- 

 morphous rodents, that of the Cape jumping hares (Pede- 

 tidae) , occupies a more isolated position, its exact relationship 

 being still somewhat obscure. But in any case, I fail to 

 deduce sufficient evidence from the distribution of these 

 hystricomorphous rodents, in favour of a direct land connec- 

 tion between South America and Africa, although there must 

 have been one between the Mediterranean region and western 

 South America by way of the West Indies and Central 

 America (see p. 280 and Fig. 14) ., 



Apart from the cape jumping hares (Pededitae), there are 

 in South Africa certain mammals which indicate a distant 

 relationship with South American ones. The peculiar pig- 

 like African edentate Orycteropus occurs in Africa, while 

 another edentate, the pangolin (Manis), inhabits Africa and 

 the Indian region. Dr. Tullberg thought that these and other 

 features implied that south-western Africa must have been 

 joined by land to South America during a time when the 

 former was completely severed from the rest of Africa. But 

 even this land bridge ceased to exist, according to Professor 

 Tullberg,* at the beginning of the Tertiary Era, at latest in 



* Tullberg, T., " System der Nagetiere," p. 498. 



