870 ORIGIN OF LIFE : IN AMERICA 



Brazil that are specifically and generically distinct from one 

 another, although more fitted for accidental dispersal across 

 the ocean than Cryptostemma is. The instances of such 

 specific or generic identity of animals and plants, in fact, are 

 scarce. Moreover, Cryptostemma is the single survivor that 

 has yet been brought to light of the otherwise extinct order 

 Meridogastra, which occupies a somewhat intermediate posi- 

 tion between the true spiders and what are called " harvest- 

 men."* For this reason it must, like Peripatus, be looked 

 upon as an exceedingly ancient relict member of our fauna. 



Let us take another group of apparently very ancient 

 animals, the worm-like and limbless coecilians, which live 

 underground. Dr. Boulengerf tells us that of the genus 

 Dermophis three species are found in Central and South 

 America, one in West Africa and another in East Africa, and 

 that the genus Herpele is confined to Gaboon in West Africa 

 and Panama. Dr. Sarasin argues that the dispersal of 

 Herpele at ,any rate dates from pre-Cretaceous times. It 

 seems possible, therefore, that these few archaic creatures 

 indicating faunistic relationship between South America and 

 Africa, have obtained their present range during some very 

 remote geological period, when the conditions of land and 

 water were entirely different from what they are at present, 

 and that they are not to be regarded as instances of accidental 

 dispersal across the Atlantic. The suggestion that South 

 America and Africa were once united by land is not a new one. 

 It has been made, as we have learnt, by various authorities on 

 entirely different grounds. Considering the contradictory 

 nature of the evidence, however, the problem requires close 

 scrutiny. 



I have already stated that Dr. Ameghino had expressed the 

 opinion, based on the evidence of the fossil mammals, that 

 South America and Africa were joined by a land bridge during 

 the whole of Upper Cretaceous times. During the Eocene 

 Period this land connection, he thinks, became more restricted 

 or narrowed down, while it still persisted incompletely as a 

 chain of islands, until middle Miocene times. Dr. Ame- 



* Karsoh, F., " Uber Cryptostemma," pp. 2529. 



t Boulenger, G. A., "Synopsis of apodal Batrachians," pp. 404 409. 



! 



