372 SUMMARY OF CHAPTERS, 



ancient and recent, make together a few grand classes. 

 We can understand, from the continued tendency to di- 

 vergence of character, why the more ancient a form is, the 

 more it genei'ally differs from those now living; why 

 ancient and extinct forms often tend to fill up gaps be- 

 tween existing forms, sometimes blending two groups, pre- 

 viously classed as distinct, into one; but more commonly 

 bringing them only a little closer together. The more 

 ancient a form is, the more often it stands in some degree 

 intermediate between groups now distinct; for the more 

 ancient a form is, the more nearly it will be related to, and 

 consequently resemble, the common progenitor of groups, 

 since become widely divergent. Extinct forms are seldom 

 directly intermediate between existing forms; but are in- 

 termediate only by a long and circuitous course through 

 other extinct and different forms. We can clearly see why 

 the organic remains of closely consecutive formations are 

 closely allied; for they are closely linked together by gen- 

 eration. We can clearly see why the remains of an inter- 

 mediate formation are intermediate in character. 



The inhabitants of the world at each successive period 

 in its history have beaten their predecessors in the race for 

 life, and are, in so far, higher in the scale, and their 

 structure has generally become more specialized; and this 

 may account for the common belief held by so many palae- 

 ontologists, that organization on the whole has progressed. 

 Extinct and ancient animals resemble to a certain extent the 

 embryos of the more recent animals belonging to the same 

 classes, and this wonderful fact receives a simple explana- 

 tion according to our views. The succession of the same 

 types of structure within the same areas during the later 

 geological periods ceases to be mysterious, and is intelligible 

 on the principle of inheritance. 



If, then, the geological record be as imperfect as many 

 believe, and it may at least be asserted that the record cannot 

 be proved to be much more perfect, the main objections to 

 the theory of natural selection are greatly diminished or 

 disappear. On the other hand, all the chief laws of 

 palaeontology plainly proclaim, as it seems to me, that 

 species have been produced by ordinary generation: old 

 forms having been supplanted by new and improved forms 

 of life, the products of Variation and the Survival of the 

 Fittest. 



