EVOLUTION. 



199 



" (2) The largest species of a group (genus, subfamily, or family, as the case may be) are 

 found where the group to which they severally belong reaches its highest development, or 

 where it has what may be termed its center of distribution .... 



"(3) The most 'typical' or most generalized representatives of a group are found also 

 near its center of distribution, outlying forms being generally more or less 'aberrant' or 

 specialized . . . . " 



1877. 



7. The Influence of Physical Conditions in the Genesis of Species. <Radical 



Review, I, No. 1, pp. 108-140, May, 1877. (Republished, by request, in the 

 Ann. Report of the Smithsonian Institution for 1905 (1906), pp. 375-402). 



"The doctrine of natural selection, or the survival of the fittest, has recently been brought 

 forward as the key to this complex problem, and is upheld by a large class of enthusiastic 

 adherents, who accept it as the full solution of the whole question. By others the conditions 

 of environment are believed to be far more influential in effecting a certain class of modifica- 

 tions, at least, than the necessarily precarious influence of natural selection," etc. 



The direct modifying influence of environment as a factor in evolution is regarded as more 

 potent than natural selection taken in the narrow sense of the "survival of the fittest." 



1880. 



8. Origin of the Instinct of Migration. <Bull. Nutt. Orn. Club, V, pp. 151-154, 



July, 1880. 



1883. 



9. Note on Exceptions to the Law of Increase in Size Northward among North 



American Birds. <Bull. Nutt. Orn. Club, VIII, pp. 80-82, April, 1883. 



In certain genera of Oscines, for the most part tropical in distribution. 



1885. 



10. Sexual Selection and the Nesting of Birds. <Auk, II, pp. 129-139, April, 1885. 



In reference to Wallace's 'Theory of Birds' Nests' (Intellectual Observer, July, 1867), and 

 Dixon's 'On the Protective Colour of Eggs' (in Seebohm's Hist. Brit. Birds, Introi., pp. x- 

 xxxv ii). 



1892. 



11. [Variations in Vertebrated Animals.] <Amer. Nat., XXVI, pp. 87-89, Jan., 1892 . 



Abstract of a paper presented at the meeting of the American Society of Naturalists held 

 in Philadelphia, Dec. 29-30, 1891, in a joint discussion of 'Definite vs. Fortuitous Variation.' 



1893. 



12. Keeler on the 'Evolution of the Colors of North American Birds.' <Auk, X, 



pp. 189-195, 377-380, April and Oct., 1893. 



A review of Charles A. Keeler's work of this title (8vo, San Francisco, 1893), adverse to 

 his theories. 



13. Beddard's 'Animal Coloration.' <Auk, X, pp. 195-199, April, 1893. 



A review of Frank E. Beddard's work of this title (8vo, London and New York, 1892), 

 with approving comment of the author's attitude respecting "protective coloration," "warn- 

 ing colors," "sexual coloration," and "mimicry," for which he finds little in support of these 

 popular theories. 



