98 MAMMALIAN DESCENT. [Lect. IV. 



those iitilisecl in the permanent forms of the Marsupial 

 animals. Indeed, that eastern monotrematous " Ant- 

 eater," the Echidna, appears to me to ha a highly 

 modified Protothere with the external modifications of 

 an Ant-eater ; arrested inwardly, and not transformed 

 throughout, hut retaining the old quasi-reptilian char- 

 acters in the deep-seated parts of his organisation. 

 Afterwards, in summing up this subject, I shall show 

 that we ourselves, by the force that works in us, long 

 before we become independent and conscious creatures, 

 hurr}^ through a series of changes parallel with 

 conditions that are utilised and permanent in stage 

 after stage of lower types. 



The Edentata lead nowhere ; they are the end and 

 consummation of all that came before them in this 

 particular line of mammalian life ; they have culminated 

 in forms of low intelHgence. If we could trace their 

 past history, and see them rise by transformation of the 

 old early forms of mammalian life, their genealogical 

 tree would be fairly typified by a spreading vine of low 

 stature, or an old well-weathered umbrella pine. 



Yet, in their birth and their nativity, they, perhaps, 

 promised as well as the Insectivora ; they must have 

 stood, so to speak, on the same level or platform — 

 once upon a time. But nature, caring for their mere 

 personal safety, with all this care, failed in the nurture 

 and development of their brain substance ; this cor- 

 relation of a strong body with a weak head, is not 



