246 



EAST AFRICAN FLORA AND FAUNA 



upon it advanced the theory that the movement of faunas is 

 always to the south. 



This theory of the northern origin of Hfe is unquestionably 



Walker &■ Boutall 



/Present Distribution HB 



tRan^e at Maximum Glaciation CHS 



Fig. 13. — Map of Present and Former Range of Alpine Flora. 



very suggestive, as it is supported by many different lines of 

 evidence, explains many difficult problems, and is itself readily 

 explained. Nevertheless, I venture to doubt its universal 

 truth. Colonies occasionally have migrated into Europe and 



