INTR OB UCTION. Ixxi 



the general doctrine of evolution. The labors of W. B. Scott and H. P. Osborne 

 should also be mentioned hei-e. 



The epoch of embryology, or the developmental study of animals, was inaugurated 

 by Agassiz in 1846. In the publication of his Contributions to the Natural History 

 of the United States, mainly devoted to the developmental history of the ccelenter- 

 ates and turtles, Agassiz was assisted by H. J. Clark. Macrady, another of Agassiz's 

 students, published some papers of importance on the Acalephs and their mode of 

 development. Desor and Girard wrote on the embryology of worms. Memoirs of a 

 high order of merit followed from the pen and pencil of Mr. Alexander Agassiz. His 

 embryology of the echinoderms appeared between 1864 and 1874; the memoir on the 

 alternation of generations of the worm, Autolytus, appeared in 1862; his paper on 

 the early stages of annelids in 1866; his remarkable memoir on the transformation of 

 Tornaria into Balanoglossus was published in 1873 ; and his elaborate embryology 

 of the Ctenophores in 1874. In 1864, Jeffries Wyman, at the time of his death the 

 leading American comparative anatomist and physiologist, published a memoir on the 

 development of the skate. Studies on the development of worms have been made by 

 J. W. Fewkes and E. B. Wilson, while J. A. Ryder, A. Agassiz, C. O. Whitman, H. 

 J. Rice, J. S. Kingsley, and H. W. Conn, have worked on the embryology of fishes. 

 That of the Amphibia has been elaborated by S. F. Clarke, W. B. Scott, and H. 

 F. Osborn, and their transformations by Mary Hinckley. The beautiful memoir of 

 Hyatt on the embryology of Ammonites was a difficult research, while the papers of 

 Morse on the early stages of the brachiopod, Terebratulina, published in 1869-73, 

 led him, by embryological as well as anatomical evidence, to transfer the brachio- 

 pods from the molluscs to the vicinity of the annelidan worms. Morse and W. K. 

 Brooks have also examined the development of Lingula. The studies of Morse on 

 the carpus and tarsus of embryo birds should also be mentioned. In 1870, 1872, and 

 1880, Packard published memoirs on the development of UmMlus, and was the first to 

 point out the affinities of its young to certain young trilobites ; and he has also published 

 papers on the embryology of the hexapodous insects. Of a high order of merit are 

 Howard Ayres' elaborate memoir on the development of the OEcanthus niveus, or tree 

 cricket, with its egg parasite (1884), and William Patten's valuable essay on the 

 embryology of the Phryganeidae (1884). S. I. Smith, W. K. Brooks, W. Faxon, E. 

 A. Birge, and E. B. Wilson have traced the metamorphoses of certain Crustacea. 

 Several entomologists, as Harris, L. Agassiz, Fitch, Riley, Scudder, Packard, Le Baron, 

 Hagen, Cabot, Walsh, Saunders, W. H. Edwards, Henry Edwards, S. A. Forbes, J. 

 A. Lintner, Otto Lugger, and others, have studied the metamorphoses of insects, while 

 the drawings in illustration of Abbot and Smith's ISTatural History of the Rarer 

 Insects of Georgia were made by Abbot, who lived several years in Georgia. In 

 1874 Emerton described the embryology of the spider, Pholcus, and in 1876 an impor- 

 tant memoir by W. K. Brooks, on the anomalous mode of development of Salpa, a 

 tunicate, appeared. J. S. Kingsley has described the metamorphoses of the ascidian, 

 Molgula. The embryology of the molluscs, especially of the oyster, has been worked 

 out by W. K. Brooks and J. A. Ryder, while E. B. Wilson has treated that of Renilla. 

 Mention should also be made of the papers by J. W. Fewkes and S. F. Clarke on the 

 development of coelenterates. In the department of embryology, great activity was 

 shown by American students when scarcely anything was being done in England or 

 France, and the United States were for twenty-five years (1850-1875) only second 

 in embryological studies to Germany, the mother of developmental zoology. More 



