158 DE- H. F. STANDING ON SUBrOSSIL 



apparently tropical, since it was at this period that the tropical African plants spread 

 into the regions now represented by the Mascarene Islands. If, then, there were, as 

 early as Oligocene times, well-differentiated Simige inhabiting South America, and if 

 at the same, or even a somewhat earlier, epoch there was extensive land-connexion 

 with a South-African region enjoying a tropical climate, is there not a strong 

 presumption that there were already in this African region Primate forms not 

 necessarily identical with, but closely allied to those of S. America 1 That this 

 African Primate stock was, before the separation of Madagascar from the mainland, 

 far advanced towards the possession of the essential Simian characteristics seems 

 to me probable. That it might, however, have retained on the one hand certain 

 primitive Prosimian characters, and on the other have acquired certain features now 

 distinguishing the Old World Monkeys rather than those of South America, is quite 

 possible. 



There is another argument Avhich points in the same direction. The sudden 

 appearance in Europe during Miocene times of such well-difi'erentiated and highly- 

 evolved forms as Drj/opithecus, PliojMtheciis, and Pliohylobates, has often puzzled 

 geologists. But is it not extremely probable that these Simians, as suggested by 

 Tullberg and others, migrated into Europe from Africa along with various other groups 

 of mammals at the time of the re-establishment of land-connexion between the 

 Palaearctic and Ethiopic regions'? But this would certainly imply that for long ages 

 before their appearance in Europe their evolution had been in progress in some part 

 or parts of the southern land-mass. And even should it prove necessary to put back 

 to an earlier date * than that assigned by Baron the last connexion between Madagascar 

 and the mainland, it would still seem quite possible that a Prosimian stock, which as 

 early as Oligocene times had produced forms so highly evolved as the Cebidse of the 

 Santa-Cruz beds, should in the South African region at the epoch of the last separation 

 of Madagascar from the mainland have reached a stage of evolution which would 

 account for all the Anthropoid features of our fossils. 



Briefly to sum up the foregoing argument :— 



(1) V/e have evidence of long-continued land-connexion between Madagascar and 

 South America. This connexion possibly lasted till the end of the Secondary 

 and well on into the Tertiary period. 



* The problem is complex because one has to account on the one hand for the presence in Madagascar of 

 such late forms as the Hippopotamus and Wild Hog, and on the other for the absence of various groups of 

 mammals which were in existence at an earlier date on the African continent. Dr. Blanford's suggestion 

 that the Bush-Pig found in Madagascar swam across a channel ten miles wide and found its way to the island 

 of Madagascar, appears to me extremely improbable, especially as one has to account for the existence in the 

 island at the present time of several distinct species. A much more probable explanation woiild seem to be 

 that a low-lying isthmus covered with dense jungle and intersected by swampy tracts connected Madagascar 

 with the mainland. Such a tract of country would offer but little obstacle to the passage of the Wild Pig, 

 but would form an effectual barrier to the incursion of almost aU other mammals, though purelj' arboreal 

 animals like Monkeys would find little difficulty in also traversing such a region. 



