430 



ANIMAL BIOLOGY 



primitive forms — Tarsioids and Lemuroids — and so back, and 

 still further back to an insectivorous stem from which the Primates 

 originally emerged. It is perhaps somewhat in deference to Man 

 that the Primates are usually placed as the culminating order of 

 Mammals and so of the Vertebrate series, because in spite of their 

 larger brain — and the use they make of it — the Primates retain 

 many primitive characters that elsewhere are found only in the 

 lowly order Insectivora. (Figs. 201, 202.) 



No useful purpose will be served at the present time by delving 

 further into the geologic past for still earlier antecedent forms, 

 because behind the Insectivores the actual record becomes in- 

 creasingly obscure. However, it seems certain that the latter were 

 evolved from still more primitive Mammals during the Mesozoic 

 Age — the Age of Reptiles ; the earliest Mammals arising from 

 the reptilian stock. 



Returning to Man as a Primate and his relationships with the 

 anthropoid apes, we are on more firm ground. This relationship 



ORANG-UTAN 

 Fig. 275. 



CHIMPANZEE GORILLA MAN 



- Feet of Anthropoid Apes and Man. (From Schultz, after 

 several authors.) 



is supported by many independent but interlocking lines of evidence, 

 such as the similarities in structure of the brain and viscera, of the 

 musculature and the skeleton in general and of the hands and feet 

 in particular. The differences are almost entirely in proportions, 

 the structures are almost identical. Indeed, even the ridges on the 

 palms and soles, and the chemical properties of the blood indicate 

 affinity. And not the least important evidence is the structure of 

 the premolar and molar teeth, because those of Man are very un- 

 like those of any other animals except the great apes. Therefore 

 the teeth, especially since they withstand well the ravages of geo- 

 logic time, afford excellent clues in the search for the fossil an- 



