Cephalization, 22, 14, 1856; 36, 1, 321, 440, 1863; 37, 10, 157, 184, 1864; 41, 163, 1866; 12, 245, 1876.
Homologies of insectean and crustacean types, 36, 233, 1863; 47, 325, 1894.
Origin of life, 41, 389, 1866.
Relations of death to life in nature, 34, 316, 1862.
Of the above, the articles on cephalization as a fundamental principle in the development of the system of animal life have attracted much attention. The evidence from comparative anatomy, paleontology, and embryology alike supports the view that advance in the ontogenetic as well as in the phylogenetic stages is correlated with the unequal growth of the cephalic region as compared with the rest of the body. Dana shows that this principle holds good for all groups of animals. His homologies of the limbs of arthropods and vertebrates, however, do not accord with more modern views.
Other papers on the same and allied topics were published by Dana in other periodicals. His most conspicuous zoological works, however, are his reports on the Zoophytes and Crustacea of the United States Exploring Expedition, 1837–1842. The former consists of 741 quarto pages and 61 folio plates, describing over 200 new species, while the Crustacea report, in two volumes, has 1620 pages and 96 folio plates, with descriptions of about 500 new species. Each of these remains to-day as the most important contribution to the classification of the respective groups. The relationships of the species, genera and families were recognized with such remarkable judgment that Dana’s admirable system of classification has remained the basis for all subsequent work.
Dana’s critical reviews (25, 202, 321, 1858) of Agassiz’s “Contribution to the Natural History of the United States” are among the most interesting of his philosophical discussions concerning the relationships of animals as revealed by their structure, their embryology, and their geological history.
The remaining zoological articles in this series cover nearly the whole range of systematic zoology. Especially important are the articles by Verrill on coelenterates, echinoderms, worms and other invertebrates.
In the years following the publication of Darwin’s Origin of Species in 1859 occur many articles on the theory of natural selection. Some of the writers attack the theory, while others give it more or less enthusiastic support.
Experimental methods in solving biological problems were little used at this time, although a few articles of this nature appear in the Journal. Of these, a paper by W. C. Minor (35, 35, 1863) on natural and artificial fission in some annelids has considerable interest to-day.