FAUNISTIC PROBLEMS 381 



It is now fifty years since Mr. Andrew Murray * first 

 directed attention to the fact that the beetle fauna of Old 

 Calabar in West Africa presented certain affinities with that 

 of South America. He even then suggested that some sort of 

 communication must once have existed between these two 

 regions of the earth. A few years later he returned to the 

 same problem, expressing the opinion that this communica- 

 tion consisted of an actual land bridge of which the only re- 

 maining vestiges are the islands of Ascension, St. Paul's, St. 

 Helena and Tristan da Cunha.f 



Great stress is also laid on this remarkable relationship 

 between the southern continents by Professor Kolbe,J but he 

 explains it by the assumption of a land bridge far to the 

 south of the Equator. 



Dr. Packard was good enough to inform me some years 

 ago that the distribution of the Lepidoptera was distinctly 

 in favour of the theory of a former union between South 

 America and Africa. He alluded in particular to a family of 

 moths known as the Saturnidae, stating that their general 

 range confirmed the view arrived at from other sources, that 

 perhaps at the close of the Cretaceous Period and through 

 the early part of the Tertiary Era the two continents were 

 connected with one another by land. 



The importance of the fresh -water crabs in the solution of 

 problems of this nature has been emphasised, as I mentioned 

 before, by Dr. Ortmann,|| who showed that the west African 

 Potamoninae are geographically most closely approached by 

 the South American Potamocarcininae, and that this suggested 

 a former union of these regions. This land bridge in its full 

 extent, he thinks, existed during the Jurassic and in early 

 Cretaceous time. In the middle of the Cretaceous Period the 

 southern Atlantic advanced northward and gradually invaded 

 the east coast of South America extending as far as the 

 Amazon valley. Guiana still remained joined to West Africa 

 during the remainder of the Cretaceous Period, and was not 



* Murray, A., " Coleoptera of Old Calabar," pp. 453454. 



t Murray, A., " Coleopterous Faunae," p. 15. 



| Kolbe, H. J., " Die Coprophagen Lamellicornier," p. 503. 



Packard, A. S., " Larval Forms of Moths," p. 280. 



|| Ortmann, A. E., "Distribution of Decapods," pp. 350 -351. 



