“First, that the unsymmetrical spiral forms of the shells of these and of all the Mollusca probably resulted from the action of the laws of heredity, modified by gravitation.
“Second, that there are many characteristics in these shells and in other groups, which are due solely to the uniform action of the physical influence of the immediate surroundings, varying with every change of locality, but constant and uniform within each locality.
“Third, that the Darwinian law of Natural Selection does not explain these relations, but applies only to the first stages in the establishment of the differences between forms or species in the same locality. That its office is to fix these in the organization and bring them within the reach of the laws of heredity.”
These views we find reiterated in his later palæontological papers. Hyatt’s views on acceleration were adopted by Neumayr.[211] Waagen,[212] from his studies on the Jurassic cephalopods, concludes that the factors in the evolution of these forms were changes in external conditions, geographical isolation, competition, and that the fundamental law was not that of Darwin, but “the law of development.” Hyatt has also shown that at first evolution was rapid. “The evolution is a purely mechanical problem in which the action of the habitat is the working agent of all the major changes; first acting upon the adult stages, as a rule, and then through heredity upon the earlier stages in successive generations.” He also shows that as the primitive forms migrated and occupied new, before barren, areas, where they met with new conditions, the organisms “changed their habits and structures rapidly to accord with these new conditions.”[213]
While the palæontological facts afford complete and abundant proofs of the modifying action of changes in the environment, Hyatt, in 1877, from his studies on sponges,[214] shows that the origin of their endless forms “can only be explained by the action of physical surroundings directly working upon the organization and producing by such direct action the modifications or common variations above described.”
Mr. A. Agassiz remarks that the effect of the nature of the bottom of the sea on sponges and rhizopods “is an all-important factor in modifying the organism.”[215]
While Hyatt’s studies were chiefly on the ammonites, molluscs, and existing sponges, Cope 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 palæontological 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.”