Geographical, Evidences 61 



and the trunk was much longer. To support the tusks 

 and the great grindstone molars, and to afford in- 

 sertion-surface for the muscles of the prehensile 

 trunk, able to lift a tree, there was need of an enor- 

 mous skull, but the tendency to an overincrease of 

 weight was counteracted by the extraordinary de- 

 velopment of air-cavities in the bones. This is but the 

 outline of a long story, which has been very carefully 

 worked out. There is a reasonable pedigree of ele- 

 phants ; the fossils cannot be read in any other way. 

 By slow processes of adding on and lopping off, com- 

 plexifying and simplifying, moulding and modify- 

 ing, a type like Mceritherium has been transformed 

 into the modern elephant. 



§6. Geographical Evidences. 



As we have mentioned, Darwin was greatly impressed 

 by the fact that there were numerous extinct ground- 

 sloths (Megatheriums and Glyptodonts in the order 

 Edentata) to be unearthed in South America, and 

 that the same geographical region was one of the 

 modern headquarters of members of the same sloth 

 and ant-eater order. There are other instances of 

 the same correspondence between the extinct and the 

 extant in the same area. It is no coincidence ! 



Remains of extinct marsupials are found in many 

 parts of the world, such as Europe and America. The 

 order was once widely represented, but the marsu- 

 pials seem to have gone to the wall before the higher 

 placental mammals, which had better brains. Except 

 the arboreal opossums of North and South America, 



