38 THE DOCTRINE OF DESCENT. 



stance, trachese with those of the Annelida — as the lateral 

 organs. 



The combination is inexplicable and paradoxical from 

 the point of view of the old system. 



Example after example might be thus accumulated 

 to show that the rigid partitions of the system are scarcely 

 raised before they are again broken down in every direc- 

 tion; and this in direct ratio with the increase of special 

 science. As before said, descriptive natural history neces- 

 sarily gained this experience. It then spoke of excep- 

 tions and deviations, without being able to adduce any 

 reason why the classes and types should be able to break 

 through their limits, and indeed most frequently without 

 feeling any need of accounting for the failure of the rigid 

 system. 



