6 THE HOUSE. 



the spelling but become useless in the pronunciation, 

 but which serve as a clue for its derivation.* On the 

 view of descent with modification we may conclude 

 that the existence of organs in a rudimentary, im- 

 perfect, or useless condition, or quite aborted, far 

 from presenting a strange difficulty, as they assur- 

 edly do on the old doctrine of creation, might even 

 have been anticipated in accordance with the views 

 here explained." 



The rudimentary parts met with in the structure 

 of the horse will be described fully in the last two 

 chapters of this work, which treat of the anatomical 

 characters of the animal. 



(2) It is, however, to the ancestral history, as 

 disclosed by paleontology, or the study of fossil 

 remains, that we must look for the more direct evi- 

 dence of the truth of the theory j and we are in a 

 better position to do this in. the case of the horse 

 than in that perhaps of any other animal, as it is one 

 of the few whose history can be traced through a 

 tolerably complete chain of links as far back as the 

 earliest Tertiary age.t We must, however, not carry 



* As, for example, the & in "debt" and "doubt." 

 t The latest of the three great periods into which geolo- 

 gists divide the age of the earth is called Tertiary or Caino- 

 zoic. It is subdivided into Eocene, Miocene, Pliocene, and 

 Pleistocene, the last being that which immediately preceded 

 the one in which we are now living. 



