supposedly primary palingenesis. Rabaud wrote: "In summary, the 'falsifications' are so pervasive that they completely mask the homologies upon which naturalists have tried to establish the filiation of organisms . . . They are sufficient to render inapplicable in practice the principle of Fritz Muller" (1916, p. 275).⁶

The response of recapitulationists was equally generous and even more frustrating. They were usually quite willing to classify most juvenile features as cenogenetic—while they stoutly maintained that such features could be recognized and separated from the palingenetic markers of ancestry. Carl Gegenbaur, Haeckel's dear friend and firm though critical supporter, wrote: "We meet on each path [of ontogenetic development] many, I would even say more, features that are never realized as permanent stages of lower creatures. They often cover the palingenetic features with a thick veil" (1888, p. 4). Yet recapitulationists retained their faith that the veil could always be lifted:

But we must not on that account "empty out the child with the bath" and con- clude that there is no such thing as a "biogenetic law" or recapitulation of the phylogeny in the ontogeny. Not only is there such a recapitulation but—as F. Muller and Haeckel have already said—ontogeny is nothing but a recapitulation of the phylogeny, only with innumerable subtractions and interpolations, additions and displacements of the organ-stages both in time and place.(Weismann, 1904, pp. 174-175)

Introduction of Juvenile Features into
the Adults of Descendants

Recapitulation requires that adult features of ancestors appear in the juvenile stages of descendants. Nothing, therefore, can be more contrary to its operation than the incorporation of previously juvenile features into the adult stages of descendants. In the 1920s Walter Garstang emphasized this contradictory process in a series of articles (1922, 1928, 1946) and a delightful book of posthumously published poetry (1951). Many have supposed that Garstang's elucidation of "paedomorphosis" disproved recapitulation.7 In fact, recapitulationists had recognized this phenomenon from the beginning; they had discussed it at length, and had catalogued as many cases as Garstang ever knew (Kollmann, 1885; Boas, 1896).

Every subject has its Drosophila; in this case, the exemplar's role is held by axolotl, a Mexican salamander that usually reproduces as an aquatic larva (see Chapters 8 and 9 for a summary of its biology). Garstang devoted one of his poems to this reluctant metamorphoser; it explains the situation better than any tedious paragraph from my pen.