CHRONOLOGICAL CATALOGUE. 41 



1857. Baird, Spencer F.— Continued. 



report into several isolated portions without any special connection as parts of a systematic 

 whole. 



"At the same time, however, as it was desirable to present a pictui-e of the zoological 

 character of the several routes, as well as to show what each party accomplished, and, as 

 many very important notes of habits and local peculiarities were made by the naturalists of 

 the different Unes, it would have been clearly an act of injustice to these gentlemen as well 

 as to their chief officers to merge all their results into one common report. For these and 

 other reasons it was finally determined that there should be prepared one general report on 

 the entire collections of the railroad surveys, to consist solely of the technical description of 

 the families, genera, and species, and of such remarks as might be necessary to show their 

 place in the systems, each species to be preceded by its synonymy, and followed by an enu- 

 meration of all the specimens collected, so arranged in tables as to show their geographical 

 distribution. 



"In addition to this general report, however, special reports by the naturalists of each line 

 were also to be prepared and published, to embrace the systematic and vernacular names of 

 their species, with a list of the specimens collected. To these special reports, were to be 

 confined all the biographies of the animals seen, all notices of their habits, peculiarities, and 

 distribution, as observed and recorded during the route. In order that there might bo no 

 misconception of the species referred to, it was concluded to give a short diagnosis of each, 

 with a reference to the page of the general report where the purely zoofogical details might 

 be found more at length. 



"The present report, therefore, is the first of the series of general reports referred to, to be 

 followed, as soon as practicable, by the remainder of the Vertebrata. The special reports on 

 the zoology of each line of survey will be found in connection with the other reports belong- 

 ing to their respective parties, in their full notices of the Ufe of our western animals, possess 

 a general and popular interest far greater than can attach to the present account of mere 

 zoological and technical details. 



" The large size of this report on the mammals collected by the railroad parties is owing to 

 several causes. In the first place, the amount of new or little known material obtained was 

 extraordinarily great. The summary of the species, at the beginning of the systematic list 

 hereafter presented, will show that very many entirely undescribed animals were procured, 

 and that, of a large number of others, previously little known, the specimens were sufficient 

 to furnish many new and interesting details of characters, both external and internal. 



" As, too, the object in calling for complete reports from the several parties was not merely 

 to show the actual results of the several expeditions, but likewise to ascertain the general 

 character of the Western Territories, I have not hesitated to include in this work all such 

 materials derived from officers stationed at military posts, and other persons elsewhere in 

 the "West, as fell under my notice. 



" In view of the large amount of new or little known species at hand, in the preparation of 

 the present report, sometimes embracing entire genera and even families, it soon became evi- 

 dent that none of the published descriptions of the old and standard species were sufficiently 

 minute and detailed to furnish the necessary means of comparison. "With the discovery of 

 forms very closely allied to or intermediate between those already known, the descriptions 

 of the latt*)r on record did not show sufficiently in what the differences consisted. It became 

 necessary, therefore, to redescribe, as far as they could bo procured, all such species, which, 

 in fact, proved finally to be nearly all previously known. The present monograph of Amer- 

 ican mammals has, in the end, grown out of the necessities referred to. 



"It will be sufficiently evident that, without the extraordinarily rich and fuU collection of 

 North American mammals belonging to the Smithsonian Institution, the monographs and 

 comparisons of species, in the present report, could not have been prepared. Independently 

 of the specimens brought in by the Pacific KaUroad surveying parties, the series in its 

 Museum, from other sources, was found to embrace nearly all the previously known species, 

 and many entirely new ones. 



"I have also made free use of the collections and library of the Philadelphia Academy of 

 Natural Sciences, for which every facility has been furnished in its hall. The examination 

 of the specimens collected by Townsend, and described by Dr. Bachman, has contributed to 

 settle some quite doubtful points, while in some rare or very costly works of its unequaled 

 natural history library I have been enabled to verify many references which would other- 

 wise have remained uncertain. 



"I regret not to have been able to examine any of the types of the new species of Audubon 

 and Bachman, as presented by the latter gentleman to the Charleston Museum. The rules 

 of that establishment do not permit specimens to leave its hall, and it was not possible to 

 visit it during the preparation of tliis report. 



"I have endeavored to make all acknowledgments of aid from systematic writers in the 

 body of the report, although it may be well to mention here that much use has been madfr 



