306 



sional points by secondary changes. . . . An analysis of the stages 

 during the life of one individual can in no way present a knowledge of its 

 ancestry, and the method of comparing non-correspondent stages of two 

 species is wrong in principle." Equally sweeping is the statement of 

 Hurst (30) : "The ontogeny is not an epitome of the phylogeny, is not 

 even a modified or 'falsified' epitome, is not a record, either perfect or im- 

 perfect of past history, is not a recapitulation of evolution." 



It would seem as though two statements could not be more flatly con- 

 tradictory than these of Hurst and Montgomery, and that of Bather quoted 

 above. Nevertheless I venture to make the seemingly paradoxical asser- 

 tion that both parties to the controversy may be right, for the simple rea- 

 son that they are talking about quite different things. This has been 

 nowhere better expressed than by Grabau (25). He says: "It has been 

 the general custom to test the validity of the recapitulation theory by the 

 embryological method; i. e.. the comparableness of the changes which the 

 individual undergoes during its embryonic period to the adults of more 

 primitive types. Usually the comparison has been with the adults of ex- 

 isting types, since in most eases these alone were available for compari- 

 son. It is no wonder, then, that such comparisons have led to innumer- 

 able errors, if not absurdities, which have placed the recapitulation theory 

 in an evil light and awakened in the minds of many serious investigators 

 doubts as to the validity of the deductions based upon this doctrine. When, 

 however, the entire life history of the individual is considered, instead of 

 only the embryonic period, and when the successive stages of epembryonic 

 development are compared with the adult characters of related types, in 

 immediately preceding geologic periods, it will be found that the funda- 

 mental principle of recapitulation is sound, and that the individuals do 

 repeat in their own epembryonic development the characters of their own 

 immediate ancestors." (Italics mine.) 



It is as a matter of fact true that the Hyatt school of paleontologists 

 have based their phylogenies on epembryonic rather than embryonic stages 

 — stages beginning with the nepionic or infantile — since in the nature of 

 the case the true embryonic stages are scarcely ever accessible to the stu- 

 dent of fossils. It is no less tine that the severest critics of the theory 

 of recapitulation have rested their case largely en the real or supposed 

 lack of correspondence between the embryonic stages and the adult stages 

 of assumed ancestors, or upon certain a priori considerations having to 



