CuAP. XIII. SUMMARY. 411 



organs, though fitted in the adult state for purposes as differ- 

 ent as is possible. Liirv:i3 are active embryos, ^vhich have 

 been specially modified in a greater or less degree in relation 

 to their habits of life, with their modifications inherited at a 

 corresponding age. On these same principles — and bearing in 

 mind that, when organs are reduced in size, either from disuse 

 or through natural selection, it will generally be at that period 

 of life when the being has to provide for its own wants, and 

 bearing in mind how strong is the force of inheritance — the 

 occurrence of rudiment;iry organs might even have been anti- 

 cipated. The importance of embryological characters and of 

 rudimentary organs in classification is intelligible, on the view 

 that a natural arrangement must be genealogical. 



Final]}-, the several classes of facts which have been con- 

 sidered in this chapter, seem to me to proclaim so plainly that 

 the innumerable species, genera, and families, with which this 

 world is peopled, are all descended, each within its own class 

 or group, from connnon parents, and have all been modified in 

 the course of descent, that I should without hesitation adopt 

 this view, even if it were unsupported by any other facts or 

 arguments. 



