488 ZOOLOGY SINCE DARWIN. 



geographical relations to other faunal areas during the different phases 

 of the earth's history. It follows from this that it is not so much the 

 phenomena of adaptation as the phylogenetic forces that are of the 

 first importance in determining the typical character of a fauna. Zoo- 

 geography becomes, therefore, an important branch of phylogeny. i 

 A. E. Wallace brought forward this conception in his famous work, The 

 Geographical Distribution of Animals, 2 and he thereby becomes the 

 master teacher of modern zoogeography. As a preliminary for its 

 further extension it appears to be necessary to pursue with the utmost 

 conscientiousness the laborious and petty task of systematically 

 describing species. 



Descriptive systematic zoology has not gained from the new doctrine 

 so much directly as indirectly, through the general increase of interest 

 in zoology and botany which led to more work in these branches than 

 ever before. Besides, it would be easy to show that the colossal increase 

 in our inventory of animal forms, rising from about 50,000 species in 

 1832 to about 150,000 to-day, should be ascribed not only to the greater 

 number of investigators in the field, but also to the development of 

 geography. Since the latter has been promoted from a servant of his- 

 tory to the rank of an independent science, and oceanographic questions 

 have become prominent, those great expeditions have been organized 

 which have given a wider character to the zoology of this period. When 

 we learn that as regards marine life the Challenger expedition of 1872- 

 1876 alone obtained nearly 8,000 new species, we are involuntarily 

 reminded of the times of Piso, Marcgravius, and Bontius, who at the 

 beginning of the seventeenth century astonished mankiud by showing 

 for the first time pictures of the dodo and of "homo sylvestris" brought 

 from "both Indies." The description of these species gave hun- 

 dreds of new races, families, and orders; and, published in thirty-two 

 quarto A^olumes with 2,629 plates, kept 60 zoologists of all the culti- 

 vated nations employed for twenty years. 3 The result of this single 



'In geographical distribution, the genealogical relations come out with special 

 clearness in those cases where it can be shown that there is a regular proportion 

 between the geographical separation and tbe morphological differences. This 

 important conformity to law was first stated by H. Spitzer in his excellent Beitriige 

 zur Descendenztheorie (Leipzig, 1886), and was shown to exist in the orders of apes 

 andstruthious birds (p. 259etseq.). This relation ought to be demonstrable in many 

 other groups of the animal kingdom. It may be stated that one of the most decided 

 opponents of the transformistic theory of descent, A. Wigand, has made his agree- 

 ment to that doctrine dependent upon the possibility of proving such a relation 

 between geographic separation and morphological difference. (A. Wigand, Der 

 Darwinismus und die Naturforschung Newton's und Cuvier's. Braunschweig, 

 1874-1877.) 



- Authorized German edition by A. B. Meyer, two volumes. Dresden, 1876. 



•'Report on the scientific results of the voyage of H. M. S. Challenger during the 

 years 1872-1876, under the command of Capt. Sir George A. Nares and the late Capt. 

 Frank Tourle Thompson. Prepared under the superintendence of the late Sir 

 C. Wyville Thomson, and now of John Murray. Fifty vols. 4°, London, 1880-1895. 



