PREFATORY NOTE 



The revision of the American bats of the Genus Myotis was 

 originally begun by the senior author alone. A preliminary review 

 was made by him on the basis of the available material in the United 

 States National Museum (including the collections of the Bureau of 

 Biological Survey, United States Department of Agriculture), the 

 Field Museum of Natural History, and the British Museum (Natural 

 History). On account of the pressure of other duties, however, he 

 was unable to bring the study to completion. The notes and mate- 

 rial were then placed in the hands of the junior author who took up 

 the revision ab initio and prepared a complete draft of the general 

 account of the species. Later, by conference and correspondence, 

 the more difficult aspects of the subject were jointly considered and 

 all divergencies of opinion were thus reduced to a basis of mutual 

 accord. The monograph in its present form sets forth the final 

 results of all this work. 



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