July 5, 1901.] 



SCIENCE. 



25 



SCIENTIFIC BOOKS. 

 A Synopsis of the Mammals of North America and 

 the Adjacent Seas. By Daniel Gikaud El- 

 liot. Publications of the Field Columbiau 

 Museum, Zoological Series, Vol, II. Chicago, 

 Field Columbian Museum ; New York City, 

 F. P. Harper ; London, R. H. Porter ; Berlin, 

 R. FriedlJinder & Son ; Paris, J. B. Bailliere 

 & Son. March, 1901. Pp. xv + 471. Pis. 

 XLIX. Text figs. 94. Price, $3.00. 

 Until the appearance of Mr. Elliot's synopsis, 

 no general work on the mammals of North 

 America had been written since 1857, the date 

 of publication by Baird of the eighth volume 

 of the Pacific Railroad Survey reports. The 

 need for a work of this kind may be appreciated 

 from the fact that the number of mammals 

 known to inhabit America north of Mexico has 

 increased, during the past forty -four years, from 

 about 300 to over 1,000. 



" This Synopsis," the author writes, " is an 

 attempt to bring together all the forms of North 

 American * mammals that have been described, 

 and which are generally considered as entitled 

 to some kind of recognition. * * * The present 

 time cannot be supposed as opportune for a final 

 and satisfactory revision of the various groups 

 * * *. That must be the work of some future 

 Mammalogist, who can bring to the task not 

 only a thoroughly unprejudiced mind, but who 

 may have acquired a more intimate acquaint- 

 ance with the quadrupeds of those sections of 

 our country, as yet little known, and whose 

 knowledge of geographical distribution of mam- 

 mals, the extent of the individual variation of 

 crania, the relationships that apparently dif- 

 ferent forms have for each other, and the 

 changes in color assumed by the pelage through- 

 out the year, and in some cases adopted by the 

 sexes, has been gained from extensive series of 

 specimens, much greater and more complete 

 than those possessed by any naturalist at the 

 present day. * * * This Synopsis, therefore, may 

 only be regarded as a starting-point upon which 

 such a final list may be founded, and does not 

 purport to indicate how many species of mam- 

 mals there are in North America, but merely to 



* Or, more correctly, species inhabiting the United 

 States and Canada, since those confined to other parts 

 of the continent are omitted. 



show how many forms are given some kind of 

 distinctive rank at the present time * * *." Ob- 

 viously the work is intended as a reflection of 

 current opinion, and not as a critical treatment 

 of the subject. Therefore it will be necessary, 

 in order to appreciate the book, to gain some 

 understanding of the tendencies of the more 

 recent work on North American mammals, and 

 also of Mr. Elliot's attitude toward the con- 

 clusions that he wishes to summarize. 



The object of systematic biology was defined 

 by Cope as the accurate statement of the re- 

 sults of organic evolution. Convenience in 

 naming and labeling individual specimens is no 

 longer to be regarded as of more than secondary 

 importance. During the past fifteen years, the 

 period of greatest activity in the study of North 

 American mammals, series of specimens aggre- 

 gating manj^ thousands of individuals have 

 been collected with the special object of show- 

 ing the results attained by the process of evo- 

 lution at the present time. These results, 

 though, not yet thoroughly understood, have 

 been found much more complex than had been 

 supposed. Species and subspecies, to use for 

 the present these obsolete terms in the absence 

 of the single word needed to i-eplace them, are 

 not invariably separated from their allies by 

 characters easy to describe. They are inter- 

 related with every degree of intricacy, and 

 it is through the study of the moi-e closely 

 allied forms that the most significant facts are 

 to be discovered. Sharply defined species have 

 lost their history and with it their chief interest. 

 No systematic work, therefore, is more impor- 

 tant than the record of minute differences ; and 

 such difficulties as are met arise from the na- 

 ture of the results which the process of evolu- 

 tion has reached, and from the inadequacy of 

 language to express all that can be detected 

 by the eye. That these difficulties are not 

 averted when ignored is the standpoint of those 

 with whose work Mr, Elliot deals. His atti- 

 tude toward it may be learned from the second 

 paragraph of the preface : 



" It is very manifest to many Naturalists that 

 too many forms have been given distinctive 

 rank, and without doubt a considerable num- 

 ber of the so-called species and subspecies con- 

 tained in this volume will eventually swell the 



