Since there are also numerous different kinds of adaptation, a phyletic line may divide at each point into several adaptive forms, which appear in the taxonomic system as species, genera, often even as whole families, while in other cases various degrees of organization have appeared in one family.
"A Mechanico-Physiological Theory of Organic Evolution"
Carl Von Nägeli
Hence the child corresponds in different periods of its development to the phyletic stages in the descent of man.
"Education: How Old The New"
James J. Walsh
But if precisely the most essential features of the organisation thus depend upon adaptation, what is left for a phyletic force to do, since it is these essential features of the structure it would have to determine?
"Darwin and Modern Science"
A.C. Seward and Others