TWO EXPLANATIONS OF CLASSIFICATION. 57 



while the great types of Cuvier have had no com- 

 mon ancestor later than the very beginning of animal 

 life on the globe. 



It is very interesting to compare the arguments 

 brought forward by the last great exponent of the 

 theory of types, and those which evolutionists to-day 

 use in support of their own views. Agassiz' " Essay 

 on Classification," appearing just before the " Origin 

 of Species," was a masterly attempt to prove the 

 theory of types. In this essay are brought forward 

 thirty different lines of argument, each of which was 

 carefully considered, and was believed to be strong 

 evidence for the views held by the author. Now an 

 examination of these arguments gives a rather sur- 

 prising result. Of the thirty lines of argument, no 

 less than twenty-six have been directly turned upon 

 their author, and are now used as arguments in 

 favor of evolution, some of them, indeed, forming 

 the strongest pieces of evidence which the evolution- 

 ist has to offer to-day, e. g., the parallel between em- 

 bryology and paleontology. Of the other four points, 

 one still remains as a difficulty for evolution, viz. : 

 the simultaneous appearance of the different types 

 in the earliest geological ages ; one of the others has 

 been disproved, while the remaining two do not at 

 present seem to have any particular significance for 

 either side of the question. This result, which must 

 have been very unexpected to Agassiz, simply indi- 

 cates what a different theory evolution has been 

 since Darwin from what it was before, and that the 

 theory which Agassiz was combating was very 

 different from the evolution of later years. Both 



