756 



SCIENCE. 



[N. S. Vol. V. No. 124. 



distributed among the chosen ones shall 

 go to this and which to that ? (3) When we 

 have made what seems to be the best con- 

 glomeration practicable with the material 

 at hand, how are we to frame descriptions 

 that will cover such incongruous assem- 

 blages and distinguish them from one 

 another ? And after all (4) why should we 

 try to unite different species under common 

 names ? It is well to remember that the 

 book of nature is not always easy to read, 

 and that in the great majority of cases we 

 know nothing of the ancestry of individual 

 species. 



A prolific source of error respecting the 

 interrelations of allied forms is the common 

 assumption that such forms are necessarily 

 derived from one another. In numerous 

 instances this is not the case, their origin 

 dating back to a common ancestor now ex- 

 tinct. Thus a species which in Pleistocene 

 times had a transcontinental distribution 

 may have given off in remote parts of its 

 range several lines of descendants, each of 

 which has since spread over so large an 

 area that the resulting forms, originally 

 widely separated, have now come to inhabit 

 contiguous areas and as a consequence are 

 assumed to intergrade. 



Possibly the skepticism of Mr. Lydekker 

 and Mr. Eoosevelt as to the validity of the 

 new species of mammals recently described 

 is a result of unconsciously overlooking the 

 wide difference in the present status of the 

 sciences of ornithology and mammalogy. 

 Eelatively, ornithology is a finished science, 

 while mammalogy is yet in its infancy. 

 Birds have been studied by scores of 

 able naturalists ; mammals by compara- 

 tively few individuals. The disproportion 

 in available material is even greater, for 

 museums containing many thousands of 

 bird skins rarely have more than a few hun- 

 dred mammals. Until recently our mu- 

 seums have made no efi'ort to secure series 

 of mammals from extreme points in their 



geographic ranges, so that specimens might 

 be placed side by side for direct comparison 

 in order to ascertain positively — instead of 

 assuming theoretically — what the defer- 

 ences really are. Even to-day no museum 

 in the world possesses anything like an 

 adequate series of any of our larger mam- 

 malia. In the few cases in which speci- 

 mens of supposed single species have been 

 brought together from widely separated 

 areas it has generally been discovered that 

 two or more species had been confounded 

 under a single name. 



In America the science of mammalogy 

 took a long sleep after the pioneer work of 

 Audubon, Bachman and Baird, which ended 

 with the publication of their great works in 

 1854 and 1857. From this time until about 

 ten years ago little advance was made. 

 Then an active interest in the subject sprang 

 up and scientific collecting really began. It 

 is probably safe to say that during the past 

 decade more mammals have been collected 

 in ISTorth America alone than were pre- 

 viously contained in all the museums of the 

 world. Furthermore, these specimens are 

 not only of infinitely better quality than 

 the old, but are accompanied by full data, 

 uniform field measurements and perfect 

 skulls. As a result, it is now becoming 

 possible, for the first time in the history of 

 the science, to bring together for actual 

 comparison series of specimens in the dif- 

 ferent groups covering the greater part of 

 the range of these groups in an entire conti- 

 nent. Is it surprising that the study of 

 such material should result in the discovery 

 of many new species ? As a matter of fact, 

 during the last ten years the number of 

 species known in liorth America has been 

 considerably more than doubled, and several 

 entirely new genera have been found. 



In criticising a recent paper of mine on 

 the coyotes, Mr. Eoosevelt says : " The im- 

 portant point is the essential likeness of all 

 the coyotes one to the other, and their 



