498 



SVIENCE. 



[N. S. Vol. XIX. No. 482. 



suddenly but gradually. It certainly seems 

 as logical that both adaptations and adapt- 

 ive agencies should show continuity as that 

 organisms should; and we should be able 

 to trace adaptations back, precisely as 

 we trace organisms, through simpler and 

 simpler conditions until we reach the ulti- 

 mate origin of them all in the simple undif- 

 ferentiated protoplasm of the original or- 

 ganisms. 



Principle 5. Inevitable Imperfection of 

 all Adaptation, — It appears to be true that 

 no feature of any organism is free to re- 

 spond unhampered to the influence of an 

 agency producing adaptation. Inevitable 

 impediments to such complete responses 

 arise from several sources— from various 

 hereditary influences, from physical and 

 chemical limitations of their powers, from 

 the necessity of providing for nutrition, 

 support and protection, from the presence 

 of other adaptations, and from the presence 

 also, it is possible, of other features highly 

 developed without reference to any utility. 

 The result of the operation of all of these 

 influences upon any feature is a state of 

 equilibrium, of which adaptation is a part, 

 no doubt usually as large a part as the 

 other conditions will permit, but frequently 

 only a minor part. In every case, there- 

 fore, adaptation must fall below its perfect 

 development, or must be imperfect. Of no 

 feature can it be true that it is all adapta- 

 tion, but it must be adaptation plus other 

 considerations, and the latter in any struc- 

 ture may collectively even outweigh the 

 former. Now it is without doubt the task 

 of the ecologist not only to determine 

 adaptation, but as well to delimit the other 

 influences which interoperate with it to 

 make structures what they are. In other 

 words, it is the task of the ecologist to 

 determine the meaning of the features of 

 the plant Avhether that meaning involves 

 adaptation or not. 



Such seems to me the nature of adapta- 



tion as indicated by the evidence we pos- 

 sess. Certainly it is true that ecology is 

 but in its beginning. W. F. Ganong. 

 Smith College, Northampton, Mass. 



SCIENTIFIC BOOKS. 

 palmer's ' INDEX GENEEUM MAMMALIUM.'* 



, Dr. Palmer's ' Index Generum Mam- 

 malium ' is a work of immense labor, pains- 

 takingly and intelligently performed, and its 

 publication will form a landmark in the his- 

 tory of mammalian nomenclature. It fur- 

 nishes not only an elaborately annotated list 

 of all the generic and family names of mam- 

 mals, recent and extinct, published since the 

 beginning of the binomial system of Linnaeus 

 down to the end of the year 1903, but the 

 introduction, besides disclosing the origin, his- 

 tory and scope of the work, furnishes a fund 

 of historic information that should most 

 favorably influence the methods of the future 

 in the bestowal and use of names by systemat- 

 ists, not only in mammalogy but in other de- 

 partments of natural history. 



The work consists of an ' introduction ' of 

 about 70 pages, followed by Parts I.-III., with 

 an appendix, and an index to Part III. Part 

 I. comprises ' Index of Genera and Subgenera ' 

 (pp. 71-717) ; Part II., includes the ' Family 

 and Subfamily Names of Mammals ' (pp. 719- 

 776) ; while Part III. is an ' Index of Genera 

 Arranged According to Orders and Families ' 

 (pp. 777-948). The appendix contains names 

 discovered too late to insert in their proper 

 places in Part I. and various additions and 

 corrections, by means of which ' the index is 

 brought down to January 1, 1904.' 



In the ' introduction ' (pp. 8-69) there is 

 first a statement of the history and purpose 

 of the work. From this it appears that the 

 work was begun by Dr. C. Hart Merriam about 



* ' Index G enerum Mammalium : A List of the 

 Genera and Families of Mammals.' By T. S. 

 Palmer, Assistant, Biological Survey. Prepared 

 under the direction of Dr. C. Hart Merriam, 

 Chief of Division of Biological Survey. North 

 America Fauna No. 23, U. S. Department of 

 Agriculture, Division of Biological Survey. Wash- 

 ington, Government Printing Office, 1904. (Jan- 

 uary 23, 1904.) 8vo, pp. 984. 



