IMPERFECTION OF THE RECORD. 9! 



ception of evolution. There have, therefore, existed 

 between the animals of to-day and their ancient an- 

 cestors a long series of intermediate links. In each 

 case these connecting individuals will differ from their 

 parents no more than the child differs from its parents 

 to-day. But the number has been so great that the 

 slight differences accumulated through the ages 

 have finally amounted to wide distinctions. If fos- 

 sil history gives us any thing like a complete record 

 of the past, all of these stages, or at least many of 

 them, ought to be found. By means of fossil links, 

 therefore, all generic and specific differences should 

 disappear in a graduated series of connective links. 

 But no one ever pretended to claim that any such 

 a series could be found. Paleontology at the time 

 of the appearance of Darwirf's book showed very 

 few such connecting links ; while to-day many more 

 are known, they are really as nothing compared 

 with the countless numbers which must have ex- 

 existed. We know enough of fossils to-day to 

 cause us to abandon hope of ever making out such 

 a complete history as the theory calls for. Perceiv- 

 ing the great lack of these intermediate stages, some 

 naturalists have been led to modify the first concep- 

 tion of evolution. Many hold the position to-day, 

 that development in the past has not always been 

 slow and gradual, but by alternate periods of rapid 

 development and comparative rest. This saltatory 

 evolution, as it is called, does not demand such a 

 long series of intermediate links. It assumes that 

 under certain unknown circumstances species are 

 very rapidly modified, and that a few generations 



