AMERICAN BATS OF THE GENERA MYOTIS AND PIZONYX 3 



the University of California is especially rich in series of west coast 

 specimens. Finally, particular mention should be made of the use- 

 fulness of the South American material belonging to the British 

 Museum. 



For the preparation of the maps we are indebted to the courtesy 

 of the Biological Survey, United States Department of Agriculture. 



ABBREVIATIONS AND MEASUREMENTS 



The following abbreviations are used, in the lists of specimens 

 examined and the tables of measurements, to indicate the several 

 institutions of whose collections the material forms a part : 



A. M. N. H. — American Museum of Natural History, New York City. 



A. N. S. P. — Academy of Natural Seieuces of Philadelphia, Pa. 



B. M. — British Museum (Natural History), London, England. 



C. A. — California Academy of Sciences, San Francisco, Calif. 

 F. M. — Field Museum of Natural History, Chicago, 111. 



K. U. — Kansas University Museum of Natural History, Lawrence, Kans. 



M. C. Z. — Museum of Comparative Zoology, Cambridge, Mass. 



U. C. — Museum of Vertebrate Zoology, University of California, Berkeley, 



Calif. 

 U. M. — University of Michigan, Ann Arbor, Mich. 

 U. S. N. M. — United States National Museum, Washington, D. C. 



When no collection is specifically indicated the specimens alluded 

 to are in the National Museum. 



Cranial measurements have all been made by the authors. The 

 tables of external measurements have been prepared by Mr. H. H. 

 Shamel of the National Museum. It is to be understood that, unless 

 there is a specific statement to the contrary, every individual included 

 in the tables of external measurements has the joints of the fingers 

 in adult condition and that every skull has the basal suture closed. 

 Wear of teeth as an index to age is indicated as follows in the tables 

 of cranial measurements: 0=no wear visible; l^wear just visible but 

 not obvious; 2= wear obvious but not obscuring the structural char- 

 acters of the upper molars; 3 = wear so far progressed as to obscure 

 the structural characters of the upper molars. In measuring skulls 

 the incisors have been excluded from both " greatest length " and 

 " mandible." The " occipital depth " does not include the sagittal 

 crest or the auditory bullae. The teeth rows were measured from 

 front surface of canine to hind surface of posterior molar. Length 

 and breadth of individual teeth were taken with dissecting micro- 

 scope and eyepiece micrometer. Quotation marks indicate that cer- 

 tain external measurements are given as recorded by the collectors 

 of the specimens. The absence of measurements of the ear shows 

 that the external measurements of a specimen were taken from the 

 dried skin. 



