[1]Most of these come from Gould (1977). Pages refer to his glossary or text. I selected these terms either because of their importance or their obscurity or both! The last paragraph summarizes much of the chapter's conclusions and implications.

[2]The retention of ancestral juvenile features by later ontogenetic descendants; also "paedomorphic" as in "a retarded jaw is paedomorphic in primates"

[3]The repetition of ancestral adult stages in embryonic or juvenile stages of descendants. Piaget adopted the biological concept in order to explain why children today have conceptions of the world that were supposedly held by adults in much earlier humans--for example childhood egocentricism recapitulates primitive beliefs about the sun revolving about the earth.