1876.] A Century's Progress in American Zodlogy. 597 
gland or France, and the United States have been for twenty- 
five years past only second in embryological studies to Germany, 
the mother of developmental zoölogy. 
Of anthropological authors, we have room only to speak of 
Morton, Davis, E. G. Squier, Pickering, L. H. Morgan, Agassiz, 
Nott and Gliddon, Wyman, J. D. Whitney, Foster, Jones, 
Abbott, Berendt, Leidy, Baird, Dall, Putnam, ©. A. White, - 
Rau, Gillman, Meigs, Jackson, Barber, and a number of men 
now in the field, chiefly of aboriginal archæology. 
The third or evolutional epoch produced an original and dis- 
tinctively American school of evolutionists. Hyatt’s memoir On 
the Parallelism between the Different Stages of Life in the Indi- 
vidual and those in the Entire Group of the Molluscous Order, 
Tetrabranchiata, was published in 1867, and several papers 
extending his views to other groups of Ammonites and Mollusks 
have appeared since then. Cope’s Origin of Genera was pub- 
lished in 1868, and his paper On the Method of Creation of 
Organic Types, in 1871. Hyatt’s views essentially agreed with 
those published by Cope, but were less general in their appli- 
cation. The theories of both authors are based mainly on the 
embryological and post-embryoni¢ changes of animals, and on 
the idea that the different degrees of acceleration and retarda- 
tion of the growth of the individual are paralleled by those of 
genera, families, orders, and classes. This hypothesis attempts 
to account for the origin of the different groups of animals, and, 
We believe, will lead to a more general and fundamental doctrine 
than natural selection. As Cope observes, the law of natural 
selection “ has been epitomized by Spencer as the ‘ survival of the 
fittest.’ This neat expression, no doubt, covers the case ; but it 
leaves the origin of the fittest entirely untouched,” and he ac- 
cordingly seeks for the causes of the origin of the fittest. Here 
© should be mentioned the writings of Baird, Allen, and Ridg- 
way on the laws of geographical distribution and climatic varia- 
tion in mammals and birds, which have revolutionized our nomen- 
cature in these classes, and bear directly on the evolution 
hypothesis, Special attempts to ascertain the probable ancestry 
of living American mammals have been made by Gill, Cope, and 
Marsh ; of cephalopod mollusks, by Hyatt; of insects, by Pack- 
ard; and of brachiopod worms, by Morse. 
Contributions to the doctrine of natural selection have been 
made by Dr, W, C. Wells, Rafinesque, Haldeman, Walsh, Riley, 
Morse, Brooks, and others. 
