was meanwhile at work on the batrachians. His
_Origin of Genera_ appeared shortly after Hyatt's first paper, but in
the same year (1866). This was followed by a series of remarkably
suggestive essays based on his extensive palaeontological work, which are
in part reprinted in his _Origin of the Fittest_ (1887); while in his
epoch-making book, _The Primary Factors of Organic Evolution_ (1896), we
have in a condensed shape a clear exposition of some of the Lamarckian
factors in their modern Neolamarckian form.

In the Introduction, p. 9, he remarks:

"In these papers by Professor Hyatt and myself is found the first
attempt to show by concrete examples of natural taxonomy that the
variations that result in evolution are not multifarious or
promiscuous, but definite and direct, contrary to the method which
seeks no origin for variations other than natural selection. In
other words, these publications constitute the first essays in
systematic evolution that appeared. By the discovery of the
paleontologic succession of modifications of the articulations of
the vertebrate, and especially mammalian, skeleton, I first
furnished an actual demonstration of the reality of the Lamarckian
factor of use, or motion, as friction, impact, and strain, as an
efficient cause of evolution."[216]

The discussion in Cope's work of kinetogenesis, or of the effects of use
and disuse, affords an extensive series of facts in support of these
factors of Lamarck's. As these two books are accessible to every one, we
need only refer the reader to them as storehouses of facts bearing on
Neolamarckism.

The present writer, from a study of the development and anatomy of
Limulus and of Arthropod ancestry, was early (1870)[217] led to adopt
Lamarckian views in preference to the theory of Natural Selection, which
never seemed to him adequate or sufficiently comprehensive to explain
the origin of variations.

In the following year,[218] from a study of the insects and other
animals of Mammoth Cave, we claimed that "the characters separating the
genera and species of animals are those inherited from adults, modified
by their physical surroundings and adaptations to changing conditions of
life, inducing certain alterations in parts which have been transmitted
with more or less rapidity, and become finally fixed and habitual."

In an essay entitled "The Ancestry of Insects"[219] (1873) we adopted
the Lamarckian factors of change