810 THE ORIGIN OF SPECIES 



form. But this inference is chiefly grounded on analogy, 

 ami it is innnaterial whether or not it be accepted. No 

 doubt it is possible, as Mr, G. H. Lewes has urged, that 

 at the first commencement of life many different forms 

 were evolved; but if so, we may conclude that only a 

 very few have left modified descendants. For, as I have 

 recently remarked in regard to the members of each great 

 kingdom, such as the Vertebrata, Articulata, etc., we 

 have distinct evidence in their embryological, homolo- 

 gous, and rudimentary structures, that within each 

 kingdom all the members are descended from a single 

 progenitor. 



"When the views advanced by me in this volume, and 

 by Mr. Wallace, or when analogous views on the origin 

 of species are generally admitted, we can dimly foresee 

 that there will be a considerable revolution in natural 

 history. Systematists will be able to pursue their labors 

 as at present; but they will not be incessantly haunted 

 by the shadowy doubt . whether this or that form be a 

 true species. This, I feel sure, and I speak after expe- 

 rience, . will be no slight relief. The endless disputes 

 whether or not some fifty species of British brambles are 

 good species will cease. Systematists will have only to 

 decide (not that this will be easy) whether any form be 

 sufiiciently constant and distinct from other forms to be 

 capable of definition; and if definable, whether the differ- 

 ences be sufficiently important to deserve a specific name. 

 This latter point will become a far more essential con- 

 sideration than it is at present; for differences, however 

 slight, between any two forms, if not blended by inter- 

 mediate gradations, are looked at by most naturalists as 

 sufl&cient to raise both forms to the rank of species. 



