Chap. XXI. AND CONCLUDING EEMARKS. 389 



but breeds from all tlie superior and neglects all tbe 

 inferior individuals. He tlius slowly but surely modi- 

 fies liis stock, and unconsciously forms a new strain. 

 So witb respect to modifications, acquired indepen- 

 dently of selection, and due to variations arising from 

 the nature of the organism and the action of the sur- 

 rounding conditions, or from changed habits of life, no 

 single pair will have been modified in a much greater 

 degree than the other pairs which inhabit the same 

 country, for all will have been continually blended 

 through free intercrossing. 



By considering the embryological structure of man, 

 — the homologies wliich he preseuts with the lower 

 animals, — the rudiments which he retains, — and the 

 reversions to which he is liable, we can partly recall 

 in imagination the former condition of our early pro- 

 genitors ; and can approximately place them in their 

 proper position in the zoological series. We thus learn 

 that man is descended from a hairy quadruped, fur- 

 nished with a tail and pointed ears, probably arboreal 

 in its habits, and an inhabitant of the Old World. 

 This creature, if its whole structure had been examined 

 bv a naturalist, would have been classed amono-st the 

 Quadrumana, as surely as would the common and still 

 more ancient progenitor of the Old and New World 

 monkeys. The Quadrumana and all the higher mam- 

 mals are probably derived from an ancient marsupial 

 animal, and this through a long line of diversified 

 forms, either from some reptile-like or some amphibian- 

 like creature, and tliis again from some fish-like animal. 

 In the dim obscurity of tlie past we can see that the 

 early jorogenitor of all the Vertebrata must have been 

 an aquatic animal, provided with branchia?, ^^ ith the two 

 sexes united in the same individual, and with tlie most 

 important organs of the body (such as the brain and 



