558 ANNUAL EEPOET SMITHSONIAN INSTITUTION, 1912. 



islands, and awakens in tlie minds of the peoples of those lands a 

 superstitious dread — a sort of instinctive horror at the sight of the 

 ghost-like representative of their first primate ancestor. 



This much of man's pedigree will, I thmk, be admitted by the great 

 majority of zoologists who are familiar with the facts; but I believe 

 we can push the line of ancestry still further back, beyond the most 

 primitive prunate into Haeckel's suborder Menotyphla, which 

 most zoologists regard as constituting two families of insectivora. 

 I need not stop to give the evidence for this opinion, for most of the 

 data and arguments in support of it have recently been summarized 

 most excellently by Dr. W. K. Gregory.^ 



This group includes the oriental tree shrews and the African 

 jumping shrews. The latter (Macroscelididse), living in the original 

 South African home of the mammalia, present extraordmarily primi- 

 tive features linking them by close bonds of affinity to the marsupials. 

 The tree shrews (Tupaiidse), however, which range from India to 

 Java, while presenting very definite evidence of kinship to their 

 humble African cousins, also display in the structure of their bodies 

 positive evidence of relationship to the stem of the aristocratic 

 primate phylum. 



Quite apart from the striking sunilarities produced by identical 

 habits and habitats, there are many structural identities in the tree 

 shrews and lemuroids, not directly associated with such habits, which 

 can be interpreted only as evidences of affinity. 



THE NEOPALLIUM AND ITS RELATION TO THE ABILITY OF LEARNING 



BY EXPERIENCE. 



Having now sketched the broad lines of man's pedigree right back 

 to the most primitive mammals, let us next consider what were the 

 outstanding factors that determined the course of his ancestors' 

 progressive evolution. 



The class mammalia, to which man belongs, is distmguished in 

 structure from all other vertebrates mamly by the size and high 

 development of the brain, and, as regards the behavior of its members, 

 by the fact that they are able in immeasurably greater degree than 

 all other anbnals, not excluduig even birds, to profit by individual 

 experience. The behavior of most, or perhaps it would be more 

 correct to say all, anhnals, however complex and nicely adapted to 

 their circumstances it may seem, is essentially instinctive; and the 

 main problem we have to solve, in attempting to explain the emer- 

 gence of the distinctive attributes of the creature which in greater 

 measure than any other has succeeded m subordmating its instincts 

 to reason, is the means by which it has become possible for the effects 

 of individual experience to be brought to bear upon conduct. 



1 "The Orders of Mammals," Bull. Amer. Mus. Nat. Hist., vol. 27, 1910, p. 321. 



