SEPARATION OF SEXES 97 



fur, hair, and adipose; deficiency of nutritive ma- 

 terial in food or irregularity in the amount accessi- 

 ble, by particularly large receptacles within the 

 body and organs specially adapted to mastication 

 and maceration ; widespread and virulent destruc- 

 tive diseases, by phagocytes, leucocytes, etc., and 

 rapid and copious reproductions, etc. In fact, that 

 so-called part of the struggle is only metaphorically 

 entitled to the name. When by natural selection, 

 through the survival of the fittest, by infinite multi- 

 plication of forms through variation, the emergence 

 of the highest types of mammalians, birds, fishes, 

 etc., of the tertiary era had been accomplished, then 

 the so-called struggle against the inanimate environ- 

 ment became less and the real struggle against the 

 living antagonists far more important, and that 

 seems to have been the time when the first upright 

 creatures came on the scene, and the period to which 

 the above argument alludes. 



Quite a number of species and varieties of mam- 

 malian creatures have been exterminated by man 

 within the last two centuries. Many more, not now 

 existing, we find mentioned in the literature of earlier 

 centuries; and it seems worth while considering 

 whether the accounts given in myths, traditions, and 

 earliest literatures of the monsters and dragons of 

 the primal age, killed by heroes, are not more ration- 

 ally explained than heretofore by believing them 

 to be accounts tainted by the inaccuracy and ten- 

 dency to exaggeration of untutored minds, but yet 



